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Model 2520 Pulsed Laser Diode Test System Service Manual

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7. Faas Ba c Nana N Or Sa Ny em ST R63 0 o SECONDARY SIDE COMPONENTS SIDE O1 NOTE FOR COMPONENT INFORMATION SEE PRODUCT STRUCTURE DO NOT POPULATE 3 A SMT MO MODEL NEXT ASSEMBLY USED ON Ime ar E m cca cc aei Lc ME p S DIM ARE IN IN UNLESS OTHERWISE NOTED 10 5 99 Que TITLE FE UE ES CE WT IE COMPONENT LAYOUT DIM TOL UNLESS OTHERWISE SPECIFIED DRN MS APPR Oo KEITHLEY INSTRUMENTS XX 01 ANG 1 INO CLEVELAND OHIO 44139 yyy 005 eae abner DO NOT SCALE THIS DRAWING C n t c qu PO PRIMARY A Nr AVA S E J UN MP ON ENTS SID E U10 a NI R fr U1 CN O fx tJ I c3 DD OO J pir C MN ERR A M 000 R50 C30 _ 4 3 O JV Ter m a ras EZ I EJ c 200000000
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9. os V O Y Lo T R82 R83 R84 M ud e E C N O nO Ao o c NVA fr Qd C AN o VJ J J J f UN Na NG M4 R R SGOMPFUNENT STRUEJORE GEFER PRD SPE GE x DO NOI POPULATE MODEL NEXT ASSEMBLY USED ON DIM ARE IN IN UNLESS OTHERWISE NOTED P TE 9 15 Q00 gt HALE 3 2 KEITHLEY INSTRUMENTS INC E C TITLE DIM TOL UNLESS OTHERWISE SPECIFIED DN Eo Waco uu SC MPONENI LAYOUI XX 01 ANG 1 ae E fail MR ING E AA VAN CLEVELAND OHIO 44139 yyx 905 D ARCEM DO NOT SCALE THIS DRAWING C Ata s Specifications A 2 Specs and Accessories LASER DIODE PULSE OR DC CURRENT SOURCE SPECIFICATIONS DRIVE CURRENT APPROX RMS NOISE SOURCE PROGRAMMING ELECTRICAL ACCURACY typical RANGE RESOLUTION RESOLUTION rdg maA 3 IkHz 20MHz 5 0 500 mA 10 HA 8 pA 0 2 0 45 70 pA 0 1 00 ADC 100gA 80 uA 0 2 4 4 5 800
10. R42 Zo crs y co FE M 01 O LU p E e K 0 0 0 0 10 00 04 0 O Eee O CRA 03 R5 0 R6 a se U25 C E Ko s O SE AENA m Q2 AA O O A Z O kk 04 05 0 0 OO S C41 E PRELIMINAR Y SES A PRELIMINAR Y a PET E 25648 RELEASED SEIN e Hs PRC DUCT A LURE Ty UO MODEL NEXT ASSEMBLY USED ON K SUE SUM E Y KEITHL CLEVE EY INSTRUME LAND OHIO NTS INC 44139 DIM ARE IN IN UNLESS OTHERWISE NOTED DIM TOL UNLESS OTHERWISE SPECIFIED ENT LAYOUT ANG FRAC 1 1 64 NOT SCALE T N L LTR ECA NO REVISION ENG A PRELIMINARY LM ELS 9 19 B PRELIMINARY ELS 10 25 00 C PRELIMINARY MS 1 D PRELIMINARY MS E 25648 RELEASED
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13. Voltage Clamp U4 U6 U16 Q9 Laser Diode Current Source High gt DAC Pulse Current Output Control Data U54 Highs Amplifiers Stage E PULSED OUT From M PU witch gt rom Low U8 U18 010 012 Terminals gt DAC U5 Ul Detector 1 Voltage Bias Source Control Data Amplifier From MPU DAG Current DETECTOR 1 UE Drive O Bias Terminal U20 Detector 2 Voltage Bias Source Control Data A Ampliner From MPU Current DETECTOR 2 0 u A Drive Bias Terminal U3 Laser Diode Voltage M easurement Sample Data to SRAM A D Pu and DSP converter Ranging PULSED SENSE F O Terminals U31 U12 U13 Detector 1 Current M easurement Sample Data V to pe AJD Converter and DSP Converter SC DETECTOR 1 m p 4 ging r O Current Input U43 U7 U8 Terminal Q10 Q11 Detector 2 Current Measurement Sample Data V to SRAM A D Converter and DSP Converter PEL DETECTOR2 wil iO i ging r O Current Input U53 U10 U17 Terminal Q15 Q16 4 8 Troubleshooting Model 2520 Pulsed Laser Diode Test System Service Manual Source circuits Voltage bias source circuits Each Model 2520 voltage bias source is a digitally controlled source that can source up to 20V 100mA Digital control information from the MPU is converted by a DAC into an equivalent analog signal U1 converts the detector 1 source data while U2 converts detector 2 source
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17. LTR ECA NO REVISION ENG DATE I90 0090 ud DETAIL A A 25821 Released ST 4 9 01 DIGITAL BOARD WIRING Al 26082 2520 100C1 Was 2520 1000 ST 1 10 01 FROM REAR PANEL CONNECTOR A2 25136 2520 100D Was 2520 100C DISPLAY BOARD CABLE Ea PLACE RIBBON CABLE AND SY PILOT LIGHT WIRES IN CABLE CLAMP E d ERE RE AA S PIN tl 4 40X1 4PPH SEI SSS 2520 100D DIGITAL BOARD ASSEMBLY dines fr a ra Fa 5 REQ D 5 IN LBS Sm ES wis 33 e HO e gt FROM PILOT LIGHT Sly vum SEE DETAIL A id un a CS 713 IEEE HARDWARE KIT 8 IN LBS lt BOO FROM REAR PANEL oS CS 725 SCREWLOCK FEMALE ie 4 REQ D 4 IN LBS ee m II RE dL p M2 5X8PPH ef REG DIGG IN LBS FOLD CABLE 2520 050 POWER MODULE POWER SUPPLY TO CHASSIS 2520 040 FRONT PANEL ASSEMBLY SA eu DICTU 2520 2520 052 Chassis Assembly SJELDNE EE N A MODEL NEXT ASSEMBLY NEXT PROCESS STEP QTY 2520 040 FRONT PANEL ASSEMBLY SE 2520 050 l POWER MODULE POWER SUPPLY TO CHASSIS DIMENSIONAL TOLERANCES E DO NOT SCALE THIS DRAWING E DATE 23 0c 00 E TITLE CS 713 IEEE HARDWARE KIT UNLESS OTHERWISE SPECIFIED Front Panel Dig Board To Chassis CS 125 4 SCREWLOCK FEMALE KX 015 ANG f M2 5X8PPH 2 METRIC PHIL PAN HEAD SCREW KETTIHILIEY 5ei tter Instruments tne Foy a ogs muc 21164 MATERIAL NO 4 40X1 4PPH 5 PHIL PAN HEAD SCREW ED Ae are 7 S m H 2520 05 LTR ECA NO REVISION ENG DATE 650 0 S ON B 25944
18. Circuit designation Description Keithley part no JA CONN 05 MINI D RIBBION 26 PINS CS 1118 1 J5 CONN HEADER 36 PINS CS 368 36 J6 CONN HEADER STRAIGHT SOLDER PIN CS 368 26 J8 J9 LATCHING HEADER FRICTON SGL ROW CS 724 3 K1 K2 K5 K10 NON LATCHING RELAY RL 242 K3 K4 K11 K12 RELAY RL 185 L1 L2 L3 L4 FERRITE BEAD CH 91 L6 L8 L11 L15 L9 L16 L18 FERRITE CHIP 600 OHM BLM32A07 CH 62 Q10 Q15 TRANS NPN SILICON 2N3904 TG 47 Q11 Q16 TRANS PNP SILICON 2N3906 TG 84 Q21 TRANS N MOSFET VN0605T TG 243 Q38 Q39 040 Q41 IC POWER VOLT REF LT1004CZ 2 5 IC 929 Q5 Q6 TRANS P CHAN MOSFET TP0610T TG 259 Q7 Q9 012 Q14 017 Q19 Q28 TRANS N MOSFET VN0605T TG 243 Q36 Q37 Q20 R1 R103 RES 121 1 100MW THICK FILM R 418 121 R10 R12 R265 R266 RES 15 1 1W THICK FILM R 418 15 R100 RES 715 1 100MW THICK FILM R 418 715 R102 R104 RES 402 1 100MW THICK FILM R 418 402 R11 R7 RES 121K 1 100MW THICK FILM R 418 121K R14 R45 RES 1 1 100MW THICK FILM R 418 1 R15 R39 R46 R69 RES 0499 1 100MW THICK FILM R 418 0499 R16 R47 RES 49 9 1 100MW THICK FILM R 418 49 9 R18 R9 RES 200K 1 1 10W METAL FILM R 263 200K R2 R3 R92 R96 R101 R221 RES 1K 1 100MW THICK FILM R 418 1K R244 R247 R90 R222 R223 RES 10K 1 100MW THICK FILM R 418 10K R238 R239 RES 59K 1 100MW THICK FILM R 418 59K R24 R250 R260 R54 RES 200 1 100MW THICK FILM R 418 200 R248 R249 RES 499 1 100MW THICK FILM R 418 499 R252 R255
19. eese 5 4 Front panel disassembly seen 5 5 Removing power components essere 5 6 Power supply module removal sess 5 6 Power module removal see 5 6 Instrument re assembly sees 5 6 Testhead disassembly sess 5 7 Case disassembly 5 eni terere ritiene ete 5 7 Output board removal sssrinin 5 7 Input board removal sse 5 7 Testhead re assembly sess 5 7 Replaceable Parts INTrOdUCH N coito 6 2 Parts USES cian 6 2 Ordering information 1 eee cierne 6 2 Factory E 6 2 Component layouts eese shoes citer charte ie dte ENEE 6 2 Specifications Calibration Reference Introduction ias iia B 2 Command summary cooccccccncncnnnonnnonnnnonnnonncnn non nc nn con nono ener B 2 Miscellaneous commands serene B 3 Measurement commands sese B 6 Current source commands essere B 7 Voltage bias source commands see B 8 Detecting calibration errors oocccnnnccnononocnnononncnnnonncnnconnconc coronan B 9 Reading the error queue sse B 9 Error SUNDAY e B 9 Status byte EAV Error Available bit B 10 Generating an SRQ on error sss B 10 Detecting calibration step completion sess B 10 Using the OPC Query terret tret eris B 10 Using the OPC commande B 11
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21. eere 2 14 Current measurement calibration values 2 18 Remote calibration command summary 2 22 Voltage measurement calibration voltages and commands 2 25 Remote current source calibration summary 2 27 Remote pulse low calibration summary 2 29 Remote voltage bias source calibration summary 2 31 Remote current measurement calibration currents and commands esee 2 33 Remote compliance calibration summary 2 36 Routine Maintenance Power hine ge sere ERES e ads eka TERM besser te Pra snes 3 3 Troubleshooting Display board checks A 4 12 Power supply checks AA 4 13 Digital circuitry checks eene 4 14 Analog circuitry checks eee 4 15 6 Table 6 1 Table 6 2 Table 6 3 Table 6 4 Table 6 5 Table B 1 Table B 2 Replaceable Parts Mainframe digital board parts list oooococncnncnnnnicnnonenenen 6 3 Mainframe display board parts list eenornrrnovrnrnrrnvernvrnneverenne 6 9 Test head board parts list see 6 10 Pulse board parts list ooooonccnocnocccccnoccnonconnnancnnnnon cnn n ran noncrnnonns 6 13 Miscellaneous parts list eee 6 16 Calibration Reference Calibration commands eene B 2 Calibration errors e nnne B 9 Performance Venfication
22. 6 O oy I e e p Y gt T vr 9en A J y o Bs o I TTT 5 EN c O OJI E x M 573 2 p O p gt Si 6d i C Ee O 782 gt Ko TO zya E Ge l SIH INI 81 E Ve 29 A als E s 3 o I Gale r o o o A amp 3 3 2 H ES CD 0O Ge S in 2 De ZIED ETEO PIED GIECO ITED LIED BIEN 6162 02ED 2 o d E ac 7 DMG DE g eS CN E Su Cr NOTE FOR COMPONENT C EA IPONENTS SIDE 01 INFORMATION SEE PRODUCT STRUCT IRE PRELIMINARY RELEASED CO ADDITIONAL COMPONENTS N R12 R21
23. Figure 4 2 shows a simplified block diagram of the analog circuits Measurement circuits Voltage measurement circuits The laser diode voltage measurement circuits consist of U12 U13 and associated cir cuitry The two sections of U12 provide buffering for the HI and LO sense lines while U13 controls ranging with appropriate feedback elements Current measurement circuits Signal conditioning for the detector input currents are provided by I V converters which convert the input signal currents to voltages that can be used by the A D converters U7 U8 Q10 and Q11 form a compound op amp for detector 1 I V conversion while U10 U17 Q15 and Q16 make up an identical op amp for detector 2 I V conversion Current ranging is provided by selecting various feedback resistors for the corresponding current ranges 10mA 20mA 50mA and 100mA A D converters Each of the three measurement channels has its own 10MHz 14 bit A D converter U31 provides A D conversion for laser diode voltage measurements while U43 and U53 perform A D conversion for detector 1 and detector 2 current measurements respectively A D digital data is stored in high speed FIFO first in first out SRAM circuits U27 U29 U38 U42 and U49 for use by the DSP section described below Model 2520 Pulsed Laser Diode Test System Service Manual Figure 4 2 Analog circuitry block diagram Troubleshooting 4 7
24. 1 4 Performance Verification Model 2520 Pulsed Laser Diode Test System Service Manual Verification test requirements Be sure that you perform the verification tests Under the proper environmental conditions After the specified warm up period Using the correct line voltage Using the proper test equipment Using the specified output signals and reading limits Environmental conditions Conduct your performance verification procedures in a test environment with An ambient temperature of 18 28 C 65 82 F A relative humidity of less than 70 unless otherwise noted Warm up period Allow the Model 2520 to warm up for a minimum of one hour before conducting the veri fication procedures If the instrument has been subjected to temperature extremes those outside the ranges stated above allow additional time for the instrument s internal temperature to stabilize Typically allow one extra hour to stabilize a unit that is 10 C 18 F outside the specified temperature range Also allow the test equipment to warm up for the minimum time specified by the manufacturer Line power The Model 2520 requires a line voltage of 100V to 240V and a line frequency of 50 or 60 Hz Verification tests must be performed within this range Model 2520 Pulsed Laser Diode Test System Service Manual Performance Verification 1 5 Recommended test equipment Table 1 1 summarizes recommended verification equipment and pertinent specifi
25. 2 19 Compliance calibration connections sess 2 20 Routine Maintenance Model 2520 rear panel sse 3 2 Troubleshooting Overall block diagram esee 4 5 Analog circuitry block diagram esee 4 7 Power supply block diagram sse 4 9 Digital circuitry block diagram esses 4 11 List of Tables 1 Table 1 1 Table 1 2 Table 1 3 Table 1 4 2 Table 2 1 Table 2 2 Table 2 3 Table 2 4 Table 2 5 Table 2 6 Table 2 7 Table 2 8 Table 2 9 Table 2 10 Table 2 11 Table 2 12 Table 2 13 Table 2 14 3 Table 3 1 4 Table 4 1 Table 4 2 Table 4 3 Table 4 4 Performance Verification Recommended verification equipment ss 1 5 Voltage measurement accuracy limits essssss 1 9 Current source verification limits esses 1 11 Current measurement verification limits 1 12 Calibration Recommended calibration equipment sss 2 5 Calibration menn c ceeselisdastss teas caves cdscecaseeevereceasesssctencvs beets 2 6 Calibration execution menu reerrrrovrrvorvnvrrrrnvrnrnvvnsvrrenneserseenn 2 6 Voltage measurement calibration values 2 11 Current source calibration values sees 2 13 Pulse low calibration values
26. ADDED CA 265 1B 8 CA 264 2 ST 4 9 01 B 25901 2520 3006 Was 2520 300F 428 303D BEZEL NOTE ORIENTATION OF WORDING 2306 307A COVER x S TRIGGER LINK E N p ES 4 40X1 4PFHUC 4 REQ D 5 IN LBS MC 285 SERIAL NUMBER DO NOT TIGHTEN UNTIL REAR BEZEL INSTALLED MC 285 SERIAL NUMBER SEE DETAIL B MC 615A WARNING LABEL MC 233A WARNING LABEL SEE DETAIL A 2520 051 FRONT PANEL CHASSIS ASSEMBLY 428 338B MOUNTING EAR 428 328E MOUNTING EAR RIGHT FA 230 2B 8 SCREW W 2 REQ D T_IN LBS AA NOTE SEND 2520 300G TEST HEAD ASSEMBLY ORIENTATIO ANN CA 264 2 amp CA 265 1B CABLES WITH UNITS TO TECH rt 224 FOOT 2 REQ D PART NUMBER QTY DESCRIPTION 2520 051 FRONT PANEL CHASSIS ASSEMBLY DETAIL A 2306 307A COVER Mecha 428 328E MOUNTING EAR RIGHT etim 428 3388 MOUNTING EAR LEFT a REAR OF UNIT FA 230 2B 2 FASTENER f a EE f KE 0 2520 2520 080 Final Inspection MC 615A WARN G LABEL 2520 Tech Tech 4 40X1 4PFHUC 4 PHIL FLAT HEAD UNDERCUT SCREW Vel TOGET T
27. 2 16 Calibration Model 2520 Pulsed Laser Diode Test System Service Manual Step 5 Voltage bias source calibration Follow the steps below to calibrate both bias voltage sources 1 Connect the DMM to the Model 2520 testhead DETECTOR 1 and VOLTAGE SENSE HI jacks as shown in Figure 2 5 Be sure to connect DMM LO to the inner shield of the DETECTOR triax cable Select the DMM DC volts function and enable auto range Press the MENU key select CAL then press ENTER Select EXECUTE then press ENTER to enter the CAL EXECUTION menu Select Vb1 then press ENTER The instrument will prompt for 20V calibration Vbias 1 CAL Press ENTER to Output 20 000 V 7 Press ENTER The instrument will display the following message DMM RDG 20 00000 V Use lt q P A Y ENTER or EXIT 8 Note the DMM voltage reading then use the EDIT keys to adjust the Model 2520 display value to agree with that reading ot an Figure 2 5 Detector 1 voltage bias source calibration connections Model 2001 DMM Input HI M odel 2520 Testhead KEITHLEY 2001 MULTIME Triax Cable iUi e 00000000 2 Inner Shield A NS gt Lid E Input LO ME el s p Ko DETECTOR 1 VOLTAGE SENSE HI Model 2520 Pulsed Laser Diode Test System Service Manual Calibration 2 17 9 Press ENTER The unit will prompt for the OV calibration point Vbias 1 CAL Press ENTER to Output 200 000 V 10 Press ENTER The instrument will displ
28. Calibration values Calibration resistance 500mA 15mA 1 5mA 1000 5A 150mA 15mA 100 Model 2520 Pulsed Laser Diode Test System Service Manual Calibration 2 15 12 Adjust the display to agree with the calculated then press ENTER The unit dis plays the following Pulse Low CAL Press ENTER to Output 15 000mA 13 Press ENTER The unit displays DMM RDG 15 000mA Use lt gt A V ENTER or EXIT 14 Note the DMM voltage reading then calculate the current from the voltage and actual resistance value I V R 15 Adjust the display to agree with the calculated then press ENTER The unit displays Pulse Low CAL Press ENTER to Output 01 500mA 16 Press ENTER The unit displays DMM RDG 01 500mA Use 4 gt A V ENTER or EXIT 17 Note the DMM voltage reading then calculate the current from the voltage and actual resistance value I V R 18 Adjust the display to agree with the calculated then press ENTER 19 Press EXIT to return to normal display 20 Disconnect the 100Q resistor and connect the 10Q resistor in its place Figure 2 4 21 Press LASER I then EDIT then use the RANGE A key to select the 5A current range 22 Repeat steps 5 through 19 for the 5A range Figure 2 4 Pulse low calibration connections 10Q or 100Q Resistor Input HI See Text Model 2520 Testhead Model 2001 DMM RANGE RANGE Input LO CURRENT CURRENT OUTPUT HI OUTPUT LO
29. D SPI CLK D SPI STB Model 2520 Pulsed Laser Diode Test System Service Manual Analog circuitry checks Troubleshooting 4 15 Table 4 4 summarizes analog circuitry checks Table 4 4 Analog circuitry checks Nn e O 3 GO JA Ch Lin P GA A ra o 10 11 12 13 14 15 16 17 18 Item component DETECTOR 1 jack TP3 TP4 DETECTOR 2 jack TP17 TP18 PULSED SENSE jacks LASER Vj range TP5 TP6 Bias source 1 U20 pin 6 Bias source 2 U3 pin 6 LASER Ij source LASER Ij source TP40 TP7 Referenced to TP6 OUTPUT ON Referenced to M20 OUTPUT ON Required condition Apply 20mA 2 5V 2 5V Apply 20mA 2 5V 2 5V Apply 10V Select 10V range 2 5V 2 5V Set to 20V 20V Set to 20V 20V 500mA range 500mA output 10V 1 4V Remarks Select detector 1 20mA range Detector 1 I V converter high output Detector 1 I V converter low output Select detector 2 20mA range Detector 2 I V converter high output Detector 2 I V converter low output Input 10V to V measure circuit V measure high output V measure low output Output 20V bias value Bias source 1 output Output 20V bias value Bias source 2 output Set to 500mA range DC mode Output 500mA I source pulse high DAC output Current amplifier input 4 16 Troubleshooting Model 2520 Pulsed Laser Diode Test System Service Manual No comm link error A No Comm Link error in
30. Generating an SRQ on calibration complete B 11 List of Illustrations 1 Figure 1 1 Figure 1 2 Figure 1 3 Figure 1 4 Figure 1 5 Figure 1 6 Figure 1 7 2 Figure 2 1 Figure 2 2 Figure 2 3 Figure 2 4 Figure 2 5 Figure 2 6 Figure 2 7 Figure 2 8 Figure 2 9 3 Figure 3 1 4 Figure 4 1 Figure 4 2 Figure 4 3 Figure 4 4 Performance Verification Testhead connections sisisi nisinsin iieis isone 1 8 Connections for voltage measurement verification tests 1 9 Connections for current source verification tests 1 10 Connections for DETECTOR 1 current measurement verification E EE 1 11 Connections for DETECTOR 2 current measurement verification tests ener 1 13 Connections for DETECTOR 1 voltage bias source verification tests enne enne 1 13 Connections for DETECTOR 2 voltage bias source verification tests sess eene 1 14 Calibration Testhead connections sse 2 10 Voltage measurement calibration connections 2 12 Current source calibration connections eeessss 2 13 Pulse low calibration connections occcccoonconnccnonnnannnononananonos 2 15 Detector 1 voltage bias source calibration connections 2 16 Detector 2 voltage bias source calibration connections 2 17 Detector 1 current measurement calibration connections 2 18 Detector 2 current measurement calibration connections
31. Query Response Description Note Example To program the calibration date cal prot date lt yyyy gt mm dd lt yyyy gt 2000 to 2099 mm 1 to 12 dd 1 to 31 cal prot date lt year gt lt month gt lt day gt The DATE command allows you to store the calibration date in instru ment EEROM for future reference You can read back the date from the instrument by using the DATE query or by using the front panel CAL menu The year month and day parameters must be delimited by commas CAL PROT DATE 2001 8 20 Send cal date 8 20 2001 To send the next calibration due date to the instrument cal prot ndue lt yyyy gt lt mm gt lt dd gt lt yyyy gt 2000 to 2099 mm 1 to 12 dd 1 to 31 cal prot ndue year month day The NDUE command allows you to store the date when calibration is next due in instrument memory You can read back the next due date by using the NDUE query or by using the front panel CAL menu The next due date parameters must be delimited by commas Send due date 8 20 2002 CAL PROT NDUE 2002 8 20 B 6 Calibration Reference Model 2520 Pulsed Laser Diode Test System Service Manual Measurement commands SEN Se CALibration PRO Tected SEN Se 1 C ALibration PRO Tected SEN Se2 C ALibration PRO Tected SEN Se3 Purpose To calibrate the active voltage or current measurement range Format cal prot sensl Cal
32. at 0 51 0 4 0 505 Current Expanded Pulse Top Current A 93 EXC A 10 15 Pulse Time us SES 2 Figure 1 1 00E 06 5 00E 07 0 00E 00 5 00E 07 1 00E 06 1 50E 06 Time Figure 3 Pulse Waveform Flatness 5A into 2 ohms T Full Pulse 7 9 20cm ulse Top M V Sense HI ag nm 0 5 in max 10 15 zs VSenseLO Bn Time us All cables SC 182 TA Figure 2 Current HT el CA Load DE Resistor Current LO o Bank Figure 4 A 6 Specifications M odel 2520 Pulsed Laser Diode Test System Service Manual Accuracy calculations The information below discusses how to calculate accuracy for both measurement and source specifications Measurement accuracy Measurement accuracy specifications are stated as follows Accuracy of reading offset As an example of how to calculate the actual limits assume an input current of 10mA on the 20mA range You can compute the limits from one year current measurement accuracy specifications as follows Accuracy of reading offset 0 3 x 10mA 65uA 30uA 651A 95uA Thus the reading limits are 10mA 95uA or from 9 905mA to 10 095mA Source accuracy Source accuracy specifications are stated as follows Accuracy of setting offset For example assume a DC source current of 200mA o
33. each channel RANGE 0 to 20VDC PROGRAMMING RESOLUTION 10mV ACCURACY 196 4 50mV CURRENT 160mA max with V Bias shorted to I Measure RMS NOISE 1kHz to 5MHz 1mV typical Specs and Accessories A 3 PHOTODIODE CURRENT MEASURE SPECIFICATIONS each channel MINIMUM DC INPUT RANGE RESOLUTION IMPEDANCE 10 00 mA 0 7 pA 100 20 00 mA 1 4 UA lt 6Q 50 00 mA 3 4 pA lt 3Q 100 0 mA 6 8 pA ce TEMPERATURE COEFFICIENT 0 18 C amp 28 50 C 0 15 x accuracy specification C ACCURACY 0 3 20 uA 0 3 65 pA 0 3 90 uA 0 3 175 uA rdg current RMS NOISE typical 90 nA 180 nA 420 nA 840 nA INPUT PROTECTION The input is protected against input shorting to the associated channel s internal bias supply The input is protected for shorts to external supplies up to 20V for up to 1 second with no damage although calibration may be affected SYSTEM SPEEDS Reading Rates ms 5 16 Number of Source Points 7 1 1018 100 18 1000 18 To Memory To GPIB GENERAL DC FLOATING VOLTAGE User may float common ground up to 10VDC from chassis ground COMMON MODE ISOLATION gt 10 Q OVERRANGE 105 of range on all measurements and voltage compliance SOURCE OUTPUT MODES Fixed DC Level Fixed Pulse Level DC Sweep linear log and list Pulse Sweep linear log and list PROGRAMMABILITY IEEE 488 SCPI 1995 0 RS 232 5 user definable power up states plus
34. soervornrnvrnrvrvvravvrrvnarnvvrvarversvennvrsnennvesnee 2 10 Remote calibra noite 2 22 Remote calibration command summary 2 22 Remote calibration procedure sess 2 23 Routine Maintenance Introduction E 3 2 Lane fuse replacement mermada 3 2 Troubleshooting eelere EE 4 2 Safety Considerations essen 4 2 Repair considerations esee 4 2 Power On EE 4 2 Front panel tests nie a 4 3 KEYS acl 4 3 DISPLAY PATTERNS test 4 3 CHAR SEL test susen needs 4 4 Principles Of op ration iternm reete terraa 4 4 Overall block diagram sse 4 4 Analog ee EE 4 6 Power supply eene te etre reper eor 4 0 IRC 4 10 Troubleshooting endrerit rper ti eter bh 4 12 Display board checks sse 4 12 Power supply checks sse 4 13 Digital circuitry checks essere 4 14 Analog circuitry checks rnnrrnvrnvvrnrnvnrrvrnrnrrvrnvrrverarnsvvrernn 4 15 No comm link error n Innen nnns 4 16 Disassembly Introduction E MO 5 2 Handling and cleaning 5 2 Handling PC boards sse 5 2 Solder repatts inicia 5 2 Static sensitive devices rrnrrrnrranvrrenrvvrrenrrnvrrnrrnververnverveesverveesve 5 3 Assembly drawings sorrnvrnnvnnvnvvnrvrnvnrvvrnvnervrevnrvevavnrevsesvsvvesvvever 5 3 Case COVER removal EE 5 4 Motherboard removal
35. ATA C ALibration PRO Tected SO U Rce3 D ATA Purpose To query detector 1 or detector 2 voltage bias calibration constants Query cal prot sour2 data cal prot sour3 data Description The CAL PROT SOUR2 DATA and CAL PROT SOUR3 DATA queries request detector and detector 2 calibration constants Returned constants are in ASCII format separated by commas Example CAL PROT SOUR2 DATA Query detector 2 constants D etecting calibration errors If an error occurs during any calibration step the Model 2520 will generate an appropriate error message Several methods to detect calibration errors are discussed below Reading the error queue As with other Model 2520 errors any calibration errors will be reported in the error queue You can read the error queue by using the SYST ERR query Error summary Table B 2 summarizes calibration errors Table B 2 Calibration errors Error number Error message 500 Date of calibration not set 501 Next date of calibration not set 502 Calibration data invalid 509 Not permitted with cal locked 510 Not permitted with cal un locked 520 Source gain data invalid 521 Source offset data invalid 522 Source gain data invalid 523 Source offset data invalid 524 Source DAC Overflow 525 Source DAC Underflow B 10 Calibration Reference Model 2520 Pulsed Laser Diode Test System Service Manual Status byte EAV Error Available bit
36. CERAMIC C 451 68P C15 C32 CAP 22PF 10 100V CERAMIC C 451 22P C19 CAP 1UF 20 50V CERAMIC C 418 1 C20 C206 C209 C210 C211 CAP 1UF 20 50V CERAMIC C 418 1 C215 C217 C27 C212 CAP 1UF 10 25V CERAMIC C 495 1 C23 C40 CAP 470P 10 100V CERAMIC C 451 470P C231 C252 CAP 1U 10 50V CERAMIC C 564 1 C24 C41 CAP 220PF 10 100V CERAMIC C 451 220P C25 C42 CAP 100P 10 100V CERAMIC C 451 100P C254 C255 CAP 33PF 10 100V CERAMIC C 451 33P C257 C259 CAP 1UF 20 50V CERAMIC C 237 1 C26 C43 CAP 47PF 10 100V CERAMIC C 451 47P C28 CAP 1UF 20 50V CERAMIC C 418 1 C3 C36 C37 C4 C44 C45 C50 C51 CAP 1UF 20 50V CERAMIC C 418 1 C56 C57 C5 C54 C55 C58 C6 C61 C63 CAP 22U 20 25V ALUM ELEC C 609 22 C69 C70 C64 C67 C68 C7 C71 C72 C8 C256 CAP 1UF 2096 50V CERAMIC C 418 1 C258 C65 C66 CAPACITOR C 606 470 C9 C10 CAP 33U 2066 6 3V TANTALUM C 561 33 CR1 CR2 CR4 CR5 ULTRAFAST POWER RECTIFIER RF 105 CR13 CR15 CR17 CR19 CR22 DIODE DUAL SWITCHING BAV99L RF 82 CR21 CR23 CR29 CR9 CR30 C31 DIODE SWITCHING MMBD914 RF 83 C14 C24 CR3 CR6 CR8 CR10 CR12 CR16 DIODE SWITCHING MMBD914 RF 83 CR18 CR20 CR32 CR33 SCHOTTKY DIODE RF 125 HS22 HEAT SINK HS 55 HS3 HS20 HEAT SINK HS 43 J1 J10 CONN BNC CS 547 J2 J3 TRIAX RECEPTACLE PCB MOUNT CS 995 Model 2520 Pulsed Laser Diode Test System Service Manual Table 6 3 continued Test head board parts list Replaceable Parts 6 11
37. Current gt 100mA 2002 SENS3 CURR RANG 100e 3 SOUR1 FUNC SHAP DC SENSE3 CURR POL POS SOUR3 VOLT 20 100mA CAL PROT SENS3 lt Current gt SOUR3 VOLT 0 OmA CAL PROT SENS3 lt Current gt SENSE3 CURR POL NEG OmA CAL PROT SENS3 lt Current gt SOUR3 VOLT 20 100mA CAL PROT SENS3 lt Current gt OUTP1 OFF Nominal values shown Calculate actual current from characterized resistance and DMM voltage reading I V R 2 36 Calibration Model 2520 Pulsed Laser Diode Test System Service Manual Step 7 Compliance calibration Follow the steps below to calibrate compliance Table 2 14 summarizes calibration steps 1 Connect the DMM to the Model 2520 testhead CURRENT OUTPUT jacks as shown in Figure 2 9 2 Select the DMM DC volts function and enable auto range 3 Put the unit into the DC mode SOURL FUNC SHAP DC 4 Send this command to turn on the source output OUTP1 ON 5 Send the following command to set the current to 100mA SOUR1 CURR 0 1 6 Set the voltage compliance to 10 5V SOURL VOLT PROT 10 5 7 Note the DMM voltage reading then send the value as the parameter for the fol lowing command CAL PROT SOUR1 PROT lt DMM Reading gt For example if the voltage is 10 45V the correct command is CAL PROT SOUR1 PROT 10 45 8 Set the voltage compliance to 3V SOURL VOLT PROT 3 9 Note the DMM voltage reading then send the value as the parameter for the fol lowing comman
38. L20 L21 FERRITE BEAD CH 91 L2 LA L15 L19 L22 L28 L30 L32 FERRITE CHIP 600 OHM BLM32A07 CH 62 L29 INDUCTOR CH 105 1 L31 INDUCTOR CH 89 1 L33 L34 L36 L39 L42 L44 FERRITE CHIP 600 OHM BLM32A07 CH 62 L47 L52 L55 L57 L35 FERRITE BEAD CH 91 Q1 Q2 TRANS N CHANNEL MOSFET BUZI1 TG 211 Q3 Q5 TRANS NPN MMBT3904 TG 238 Q4 Q6 Q11 TRANS N MOSFET VN0605T TG 243 R1 R2 R13 R14 R34 R37 R59 R61 RES 10K 1 100MW THICK FILM R 418 10K R68 R73 R111 R113 RES 100 1 100MW THICK FILM R 418 100 R117 R122 R146 RES 4 75K 1 100MW THICK FILM R 418 4 75K R118 R119 R126 R129 R139 RES 100 1 100MW THICK FILM R 418 100 R120 RES 15k 1 100MW THICK FILM R 418 15K R123 RES 499 1 100MW THICK FILM R 418 499 R125 RES 2 21K 1 100MW THICK FILM R 418 2 21K R130 R132 R147 RES 475 1 100MW THICK FILM R 418 475 6 6 Replaceable Parts Table 6 1 continued Mainframe digital board parts list Model 2520 Pulsed Laser Diode Test System Service Manual Circuit designation Description Keithley part no R131 RES 24 3 1 100MW THICK FILM R 418 24 3 R133 R136 R138 R163 R165 R175 RES IK 1 100MW THICK FILM R 418 1K R134 RES 30 1K 1 100MW THICK FILM R 418 30 1K R135 R137 RES 200 1 100MW THICK FILM R 418 200 R140 R167 R169 RES 100 1 100MW THICK FILM R 418 100 R15 R16 R38 R40 THICK FILM SMT TF 278 100 R152 R154 R155 RES 475 1 1 4W METAL FILM R 391 475 R158 R159 R160 R161 RES 226 1
39. LOW Model 2520 Pulsed Laser Diode Test System Service Manual CALibration PRO Tected SO U Rce 1 LO W CALibration PRO Tected SO U Rce 1 LO W D ATA Purpose Format Query Description Example To calibrate the low output level DAC cal prot sourl low cal prot sourl low data The CAL PROT SOUR1 LOW command calibrates the current source low output level DAC The CAL PROT SOUR1 LOW DATA query requests low output level DAC calibration constants Returned constants are in ASCII format separated by commas CAL PROT SOUR1 LOW Calibrate low output level DAC Voltage bias source commands SO U Rce CALibration PRO Tected SO U Rce2 CALibration PRO Tected SO U Rce3 Purpose Format Parameters Description Example To calibrate the detector 1 or detector 2 voltage bias source cal prot sour2 lt DMM reading gt cal prot sour3 lt DMM reading gt DMM reading gt 18 to 22V 0 5 to 0 5 18 to 22V The CAL PROT SOUR2 and CAL PROT SOUR3 commands calibrate the detector 1 or detector 2 voltage bias source respectively During the calibration process this command is sent three times once each with parameters of approximately 20V OV and 20V The voltage parame ters are determined from a DMM reading CAL PROT SOUR2 20 Calibrate detector 1 bias source Model 2520 Pulsed Laser Diode Test System Service Manual Calibration Reference B 9 DATA C ALibration PRO Tected SO U Rce2 D
40. OTHERW UNLESS FRAC LI EN Ha TP 98 F IN UNLE IN NJ 9 cy gt H LJ o e e oc E a nOs gt w x Step E a a EZ m ZTN Ly SY les A EE E DOE Mr 9000 ac A me aes ul ALLI 2 e o xx 7 e d SE 0000 z Y el DUU Gr gt M r o 8 Vo S N ES p VOU A ach Ar e eco IF Er t SS X kou a i E I Sal ID SEE PRODUC Q4 NE V N JE ie INSTRUMENTS OHIO if KEITHLEY E TS CLEVELAND
41. R258 R259 R36 RES 24 3 1 100MW THICK FILM R 418 24 3 R37 R66 R67 R256 R257 RES 24 3 1 100MW THICK FILM R 418 24 3 R262 R263 RES 1M 1 100MW THICK FILM R 418 1M R26 R35 R56 R65 RES 249 1 1W THIN FILM R 438 249 6 12 Replaceable Parts Table 6 3 continued Test head board parts list Model 2520 Pulsed Laser Diode Test System Service Manual Circuit designation Description Keithley part no R4 R6 RES 8 98K 1 125W THIN FILM R 456 8 98K R40 R41 R70 R71 RES 1 1K 1 125W THIN FILM R 456 1 1K R42 R43 R72 R73 R88 R89 RES 49 9 1 1 4W METAL FILM R 391 49 9 R5 R8 RES 10K 1 125W THIN FILM R 456 10K R76 R79 RES 402 1 125W THIN FILM R 456 402 R80 R83 RES 80 6 1 125W THIN FILM R 456 80 6 R84 R85 R86 R87 RES 121 1 125W THIN FILM R 456 121 R91 R224 RES 249 1 100MW THICK FILM R 418 249 R97 R98 R99 RES 100 1 100MW THICK FILM R 418 100 TP1 TP2 TP10 TP12 TP20 TP23 SURFACE MOUNT PCB TEST POINT CS 1026 TP6 TP25 TP27 CONN TESTPOINT CS 985 U1 U2 IC 5V 12 BIT DAC IC 1329 U10 U12 U13 U8 IC HIGH SPEED OP AMP DUAL IC 1429 Ull IC POS NAND GATES INVERT 74HCT14 IC 656 U20 U3 IC HIGH VOLTAGE OP AMP IC 1414 U21 IC 3 TO 8 LINE DECODER IC 1378 U22 IC 5V VOLTAGE REGULATOR IC 576 LM2940CT U23 IC 5V LOW DROPOUT REGULATOR IC 1370 U4 U5 U6 IC 8 STAGE SHIFT C074HC409AM IC 1026 U9 IC HCPL0631 PACK IC 1153 RES 499 1 1 4W METAL FILM R 391 499 TRANS CURR REG CDLL53
42. SCALE THIS DRAWING UNLESS OTHERWISE SPECIFIED XX 015 ANG f Keithley Instruments Inc E KEITHLEY a Ohio 44138 XXX 2 005 FRAC 81 64 y REF BERG PIN DES OPENINGS PIN Hl 2520 2520 052 Chossis Analog Board Ass y MODEL NEXT ASSEMBLY NEXT PROCESS STEP QTY USED ON Fro SURFACE MAX Wa t Panel Assembly OP 6 2920 040 LTR ECA NO REVISION ENG DATE 0S0 0 S B 26048 Add 2520 330A T 1972 Was T 1918 FROM POWER on MODULE POWER MODULE DETAIL A RED 2520 004 SC 73 s GRN YEL 3 374 4 40X1 4PPH C x Nc 4 REQ D 3 IN LBS Sy PS 41C POWER SUPPLY NE NE 2520 329A BRACKET BLU 11 3 4 CO CC 38 2 CABLE TIE 4 40KEPNUT ae 2 REQ D 5 IN LBS O e PLACE WIRES IN CABLE NN ON SIDE OF CHASSIS 2520 330A SAFTEY COVER FOLD AT SCORED LINE BEFORE INSTALLING INSTALL 1 FROM EDGE DETAIL B REF REAR PANEL 2520 004 CS 638 3 ASSEMBLY CA 266 1B CABLE PLACE IN CABLE CLAMP LU 100 LUG 4 M2 5X8PPH 2 REQ D 3 IN LBS CS 15 CONNECTOR SEE DETAIL B 4 SUPPLIED NUT 3 15 IN LBS BENI E CC 37 CABLE
43. SENS2 lt Current gt SENSE2 CURR POL NEG OmA CAL PROT SENS2 lt Current gt SOUR2 VOLT 20 100mA CAL PROT SENS2 lt Current gt OUTP1 OFF Detector 2 10mA 2KQ OUTP1 ON SENS3 CURR RANG 10e 3 SOUR1 FUNC SHAP DC SENSE3 CURR POL POS SOUR3 VOLT 20 10mA CAL PROT SENS3 lt Current gt SOUR3 VOLT 0 OmA CAL PROT SENS3 lt Current gt SENSE3 CURR POL NEG OmA CAL PROT SENS3 lt Current gt SOUR3 VOLT 20 10mA CAL PROT SENS3 lt Current gt 20mA 1kQ SENS3 CURR RANG 20e 3 SOUR1 FUNC SHAP DC SENSE3 CURR POL POS SOUR3 VOLT 20 20mA CAL PROT SENS3 lt Current gt SOUR3 VOLT 0 OmA CAL PROT SENS3 lt Current gt SENSE3 CURR POL NEG OmA CAL PROT SENS3 lt Current gt SOUR3 VOLT 20 20mA CAL PROT SENS3 lt Current gt Nominal values shown Calculate actual current from characterized resistance and DMM voltage reading I V R Model 2520 Pulsed Laser Diode Test System Service Manual Calibration 2 35 Table 2 13 continued Remote current measurement calibration currents and commands Calibration Channel Current range Test resistor currents Calibration commands Detector2 50mA 4002 SENS3 CURR RANG 50e 3 SOUR1 FUNC SHAP DC SENSE3 CURR POL POS SOUR3 VOLT 20 50mA CAL PROT SENS3 lt Current gt SOUR3 VOLT 0 OmA CAL PROT SENS3 lt Current gt SENSE3 CURR POL NEG OmA CAL PROT SENS3 lt Current gt SOUR3 VOLT 20 50mA CAL PROT SENS3 lt
44. The five parts of the test sequence are as follows e Checkerboard pattern alternate pixels on and all annunciators e Checkerboard pattern and the annunciators that are on during normal operation Horizontal lines pixels of the first digit are sequenced e Vertical lines pixels of the first digit are sequenced e Each digit and adjacent annunciator is sequenced All the pixels of the selected digit are on 4 4 Troubleshooting M odel 2520 Pulsed Laser Diode Test System Service Manual 5 When finished abort the display test by pressing EXIT The instrument returns to the FRONT PANEL TESTS MENU Continue pressing EXIT to back out of the menu structure CHAR SET test The character set test lets you display all characters Perform the following steps to run the character set test 1 Display the MAIN MENU by pressing the MENU key Select TEST and press ENTER to display the SELF TEST MENU 3 Select DISPLAY TESTS and press ENTER to display the following menu FRONT PAN EL TESTS KEYS DISPLAY PATTERN S CH AR GET 4 Select CHAR SET and press ENTER to start the character set test Press any key except EXIT to cycle through all displayable characters 5 When finished abort the character set test by pressing EXIT The instrument returns to the FRONT PANEL TESTS MENU Continue pressing EXIT to back out of the menu structure Principles of operation The following information is provided to support the troubleshooting te
45. Whenever an error is available in the error queue the EAV Error Available bit bit 2 of the status byte will be set Use the STB query to obtain the status byte then test bit 2 to see if it is set If the EAV bit is set an error has occurred and you can use the appropriate error query to read the error and at the same time clear the EAV bit in the status byte Generating an SRQ on error To program the instrument to generate an IEEE 488 bus SRQ Service Request when an error occurs send the following command SRE 4 This command will enable SRQ when the EAV bit is set You can then read the status byte and error queue as outlined above to check for errors and to determine the exact nature of the error Detecting calibration step completion When sending remote calibration commands you must wait until the instrument com pletes the current operation before sending another command You can use either OPC or OPC to help determine when each calibration step is completed Using the O PC query With the OPC operation complete query the instrument will place an ASCII 1 in the output queue when it has completed each step To determine when the OPC response is ready do the following 1 Repeatedly test the MAV Message Available bit bit 4 in the status byte and wait until it is set You can request the status byte by using the STB query 2 When MAV is set a message is available in the output queue and you can read the
46. constants SOURce 1 lt NRf gt Calibrate active current source range DATA Query current source calibration constants PROTection Calibrate voltage compliance DAC DATA Query voltage compliance DAC calibration constants LOW Calibrate low current output level DAC DATA Query low current output level DAC calibration constants SOURce2 lt NRf gt Calibrate detector voltage bias source DATA Query detector I voltage bias source calibration constants SOURce3 lt NRf gt Calibrate detector 2 voltage bias source DATA Query detector 2 voltage bias source calibration constants DATE lt yyyy gt lt mm gt lt dd gt Program calibration year month day DATE Query calibration date NDUE lt yyyy gt lt mm gt lt dd gt Program calibration due year month day NDUE Query calibration due date SAVE Save calibration data in EEPROM LOCK Lock out calibration LOCK Query if calibration is locked 1 locked 0 unlocked COUNt Query number of times Model 2520 has been calibrated Model 2520 Pulsed Laser Diode Test System Service Manual Calibration Reference B 3 Miscellaneous commands Miscellaneous commands are those commands that perform such functions as unlocking calibration saving calibration constants locking out calibration and programming date parameters CODE CALibration PRO Tected CO DE Purpose Format Parameter Description Note Example COUNT To unlock calibration ena
47. could cause degraded performance Handling PC boards Observe the following precautions when handling PC boards e Wear cotton gloves e Only handle PC boards by the edges and shields e Do not touch any board traces or components not associated with repair e Do not touch areas adjacent to electrical contacts e Use dry nitrogen gas to clean dust off PC boards Solder repairs Observe the following precautions when you must solder a circuit board e Use an OA based organic activated flux and take care not to spread the flux to other areas of the circuit board Remove the flux from the work area when you have finished the repair by using pure water with clean foam tipped swabs or a clean soft brush Once you have removed the flux swab only the repair area with methanol then blow dry the board with dry nitrogen gas e After cleaning allow the board to dry in a 50 C low humidity environment for several hours Model 2520 Pulsed Laser Diode Test System Service Manual Disassembly 5 3 Static sensitive devices CMOS devices operate at very high impedance levels Therefore any static that builds up on you or your clothing may be sufficient to destroy these devices if they are not handled properly Use the following precautions to avoid damaging them CAUTION Many CMOS devices are installed in the Model 2520 Handle all semi conductor devices as being static sensitive Transport and handle ICs only in containers specia
48. data Gain and 100mA drive capability for detector 1 and detector 2 sources respectively are provided by U20 and U3 to provide the full 20V 100mA output capability for each source Current pulse source circuits The Model 2520 current source can output a maximum current of IA DC 10V 10W or SA 9V 45W current pulses DC and pulse high current source data from the MPU is converted into an analog signal by a 16 bit DAC made up of U54 and associated components Pulse low data is converted by DAC UI and US performs pulse high low switching The signal from US is amplified by the current amplifiers U8 and U18 and applied to the output stage Q10 Q12 which provides the current drive capability for the current source The voltage clamp circuit made up of U4 U6 U16 and Q9 maintains the output voltage at the programmed compliance value regardless of load while the compliance detection cir cuit made up of U9 and U19 provides feedback to the MPU for an over compliance condi tion Over temperature detection for the current source is performed by RT1 R46 U15 and associated components Model 2520 Pulsed Laser Diode Test System Service Manual Troubleshooting 4 9 Power supply Figure 4 3 shows a block diagram of the Model 2520 power supply system The supply has two separate power transformers T1 and T2 as well as both regulated and unregulated supply voltages Unregulated circuits include the 8VF1 supply and 25VF1 supply that
49. factory default and RST DIGITAL INTERFACE Safety Interlock External mechanical contact connector and removable key switch Aux Supply 5V 300mA supply Digital I O 2 trigger input 4 TTL Relay Drive outputs 33V amp 500mA max diode clamped Tlink 6 programmable trigger input outputs Pulse Trigger Out BNC 5V 509 output impedance output trigger corresponding to current source pulse pulse to trigger delay lt 100ns See Figure 3 MAINS INPUT 100V to 240V rms 50 60Hz 140VA WARRANTY 1 year EMC Complies to European Union Directive 89 336 EEC EN61326 1 SAFETY Conforms to European Union Directive 73 23 EEC EN61010 1 CAT 1 VIBRATION MIL PRF 28800F Class 3 Random WARM UP 1 hour to rated accuracy DIMENSIONS WEIGHT Main Chassis bench configuration with handle amp feet 105mm high x 238mm wide x 416mm deep 4 in x 9 in x 16 in 2 67kg 5 90 lbs Remote Test Head 95mm high x 178mm deep with interlock key installed x 216mm wide 31 in x 7 in x 8 in 1 23kg 2 70Ibs Cable Length From Main Unit to Remote Test Head 2 1m 83 in ENVIRONMENT Operating 0 50 C 70 R H up to 35 C Derate 3 R H C 35 50 C Storage 25 to 65 C A 4 Specs and Accessories Notes 1 I year 23 C 5 C 2 If 4 Duty Cycle I exceeds 0 2 accuracy specifications must be derated with an additional error term as follows 500mA Range 30 196 rdg YD I K 5A Range 0 3 rdg YD I K w
50. fuse continues to blow a circuit malfunction exists and must be corrected Refer to the troubleshooting information in Section 4 of this manual for additional information Table 3 1 Power line fuse Line voltage Fuse rating Keithley part no 100 240V 1 6A slow blow 250V 5 x 20mm FU 106 1 6 4 Troubleshooting 4 2 Troubleshooting Model 2520 Pulsed Laser Diode Test System Service Manual Introduction This section of the manual will assist you in troubleshooting and repairing the Model 2520 Pulsed Laser Diode Test System Included are self tests test procedures troubleshooting tables and circuit descriptions Note that disassembly instructions are located in Section 5 and component layout drawings are at the end of Section 6 Safety considerations WARNING The information in this section is intended for qualified service person nel only Do not perform these procedures unless you are qualified to do so Some of these procedures may expose you to hazardous voltages that could cause personal injury or death Use caution when working with hazardous voltages Repair considerations Before making any repairs to the Model 2520 be sure to read the following considerations CAUTION The PC boards are built using surface mount techniques and require specialized equipment and skills for repair If you are not equipped and or qualified it is strongly recommended that you send the unit back to the factory for repai
51. in this section deals with routine type maintenance that can be performed by the operator and includes information on line fuse replacement Line fuse replacement WARNING Disconnect the line cord at the rear panel and remove all test leads connected to the instrument before replacing the line fuse The power line fuse is accessible from the rear panel and is integral with the AC power module see Figure 3 1 Figure 3 1 Model 2520 rear panel WARNING no INTERNAL OPERATOR SERVICABLE PARTS SERVICE BY QUALIFIED PERSONNEL ONLY mg KEITHLEY MADE IN San r CHANGE IEEE ADDRESS U S A pinse om e WITH FRONT PANEL MENU o quo de TRIGGER LINK RS 232 LINE FUSE SLOWBLOW 1 6A 250V LINE RATING 100 240VAC 50 60Hz TESTHEAD CONN 2 140VA MAX J 8 CAUTION For CONTINUED PROTECTION AGAINST FIRE HAZARD REPLACE FUSE WITH SAME TYPE AND RATING Line Fuse Model 2520 Pulsed Laser Diode Test System Service Manual Routine M aintenance 3 3 Perform the following steps to replace the line fuse 1 Using a small flat blade screwdriver carefully release the locking tab that secures the fuse carrier to the power module 2 Pull out the fuse carrier and replace the fuse with the type specified in Table 3 1 CAUTION To prevent instrument damage use only the fuse rating and type spec ified in Table 3 1 3 Re install the fuse carrier pushing it in firmly until it locks into place NOTE If the power line
52. interlock must not be defeated The testhead key control must be used to prevent operation unless authorized by the responsible body This requirement must be part of the facilities administrative controls for laser safety Outputs cannot be turned on with the key removed When servicing the test system any required personnel protection equipment e g laser safety goggles must be provided by the cus tomer s responsible body The customer s laser safety officer LSO must review and approve all installations before they are put into operation Any safety con cerns must be immediately reported to the customer s LSO If at any time the indicators provided on the testhead for INTER LOCK STATUS or LASER POWER ON should fail to light or properly indicate status immediately contact a Keithley service representative for repair Failure to do so may expose the user to hazards without proper warnings See Interlock status indicator test sequence in Section 9 of the User s manual for details on test ing the indicator lights Maximum isolation from earth ground is 10V Exceeding this value may result in a shock hazard When making connections do not leave any exposed connections Ensure that all external circuits are properly insulated NOTE Ifthe instrument is still under warranty and its performance is outside specified limits contact your Keithley representative or the factory to determine the cor rect course of action
53. on its output Send the following command to calibrate the 10V point CAL PRO T SEN S1 10 Reverse the calibrator HI and LO connections Send the following commands to calibrate the negative full range voltage point DIAG KEIT FCON HI OFF DIAG KEIT FCON LO ON SEN S1 VOLT POL NEG CAL PRO T SEN S1 10 DIAG KEIT FCON LO OFF Repeat steps 2 through 9 for the 5V range using Table 2 9 as a guide Be sure to e Select the SV range using the SENS1 VOLT RANG 5 command e Send the appropriate calibration voltage values with the CAL PROT SENSI Voltage command Model 2520 Pulsed Laser Diode Test System Service Manual Table 2 9 Calibration Voltage measurement calibration voltages and commands 2 25 Voltage range Calibration voltages Calibration commands 5V 5 00000 V 5 00000V SOURI FUNC SHAP DC SENS1 VOLT RANG 5 DIAG KEIT FCON HI ON DIAG KEIT FCON LO ON SENS1 VOLT POL NEG CAL PROT SENS 1 0 SENS1 VOLT POL POS CAL PROT SENS 1 0 DIAG KEIT FCON LO OFF CAL PROT SENS1 5 DIAG KEIT FCON HI OFF DIAG KEIT FCON LO ON SENS1 VOLT POL NEG CAL PROT SENS1 5 DIAG KEIT FCON LO OFF 10V 10 0000V 10 0000V SOURI FUNC SHAP DC SENS1 VOLT RANG 10 DIAG KEIT FCON HI ON DIAG KEIT FCON LO ON SENS1 VOLT POL NEG CAL PROT SENS1 0 SENS1 VOLT POL POS CAL PROT SENS1 0 DIAG KEIT FCON LO OFF CAL PROT SENS1 10 DIAG KEIT FCON HI OFF DIAG KEIT FCON LO ON SENS1 VOLT POL N
54. or down To remove the handle swing the handle below the bottom surface of the case and back until the orientation arrows on the handles line up with the orienta tion arrows on the mounting ears With the arrows lined up pull the ends of the handle away from the case 2 Remove mounting ears Remove the screw that secures each mounting ear Pull down and out on each mounting ear NOTE When re installing the mounting ears make sure to mount the right ear to the right side of the chassis and the left ear to the left side of the chassis Each ear is marked RIGHT or LEFT on its inside surface 3 Remove rear bezel To remove the rear bezel loosen the two screws that secure the rear bezel to the chassis then pull the bezel away from the case 4 Remove bottom screws Remove the six screws that secure the case to the chas sis They are located on the bottom of the case 5 Remove chassis To remove the case grasp the front bezel of the instrument and carefully slide the chassis forward Slide the chassis out of the metal case Motherboard removal Perform the following steps to remove the motherboard This procedure assumes that the case cover is already removed 1 Remove the IEEE 488 DIGITAL I O RS 232 and TESTHEAD CONN 1 fasten ers The IEEE 488 DIGITAL I O RS 232 and TESTHEAD CONN 1 connectors each have two screws that secure the connectors to the rear panel Remove these screws 2 Remove the motherboard moun
55. pA 0 5 00 A Pulse OFF CURRENT APPROX PROGRAMMING ELECTRICAL ACCURACY RANGE RESOLUTION RESOLUTION rdg mA 0 15 mA I p 7 nA typ 0 2 0 45 0 150 mA 10 pA 70 nA typ 0 2 4 5 TEMPERATURE COEFFICIENT 0 18 C amp 28 50 C 0 15 x accuracy specification C PULSE ON TIME 500ns to 5ms 100ns programming resolution PULSE OFF TIME 20us to 500ms 10us programming resolution valid only in sweep mode PULSE DUTY CYCLE 0 to 100 for I lt 1 0A 0 to 4 for I gt 1 0A VOLTAGE COMPLIANCE 3V to 10V 10mV programming resolution POLARITY 1 quadrant source polarity reversal available through internal relay inversion OUTPUT OFF lt 200mQ short across laser diode measured at Remote Test Head connector PULSE RISE FALL SETTING PULSE OVERSHOOT TIME 9 10 AND RANGE LOAD MODE MAX 89 TYPICAL MAX 500 mA 10Q Watt Fast 1 0 55 ns 80 ns 500mA 102 Watt Slow 0 1 lus 13 ps 5 00 A L5Q91Watt Fast 1 0 100ns 130ns 5 00 A 15Q1Watt Slow 0 1 1 us 1 3 us LASER DIODE VOLTAGE MEASURE SPECIFICATIONS MINIMUM ACCURACY RANGE RESOLUTION rdg volts RMS NOISE typical 5 000 V 0 33 mV 0 3 6 5 mV 60 uV 10 00V 0 66 mV 0 3 8 mV 120 uV TEMPERATURE COEFFICIENT 0 18 C amp 28 50 C 0 15 x accuracy specification C MAX LEAD RESISTANCE 100Q for rated accuracy INPUT IMPEDANCE 2MQ differential IMQ from each input to common Input bias current 7 5uA max PHOTODIODE VOLTAGE BIAS SOURCE SPECIFICATIONS
56. 0ppm using the 4 wire ohms function of the digital multimeter before use Use the characterized values when performing the calibration procedure 2 6 Calibration Calibration menus Model 2520 Pulsed Laser Diode Test System Service Manual Table 2 2 summarizes the main calibration menu selections To enter the calibration menu press the MENU key select CAL then press ENTER Use the EDIT keys to move the cur sor and scroll through menu selections Press ENTER to select a MENU item Table 2 2 Calibration menu Menu selection Description UNLOCK Unlock calibration using password default 002520 EXECUTE Execute calibration steps for present range VIEW DATES View calibration dates SAVE Save calibration constants LOCK Lock out calibration CHANGE PASSWORD Change calibration password Table 2 3 summarizes the calibration execute menu Each of these functions is covered in detail below Table 2 3 Calibration execution menu Menu selection Function calibrated VL Laser voltage measure IL Laser current source COMPLIANCE Laser source compliance PULS_LOW Laser source pulse low Ipd1 Detector 1 current measure Vbl Detector 1 voltage bias source Ipd2 Detector 2 current measure Vb2 Detector 2 voltage bias source Model 2520 Pulsed Laser Diode Test System Service Manual Calibration 2 7 Unlocking calibration Before performing calibration you must first unlock calibration by entering or
57. 1 U31 U43 U53 IC 14 BIT MSPS A D CONVERTOR LSI 264 U32 U44 U56 IC CMOS ANAL SWITCH DG444DY IC 866 U33 U45 U57 IC HIGH SPEED OP AMP DUAL IC 1429 U35 IC PROTECTED QUAD POWER DRIVERS 1C 1212 U36 IC STEP DOWN VOLTAGE REGULATOR IC 1369 U37 PROGRAMMED ROM 2520 801B01 6 8 Replaceable Parts Table 6 1 continued Mainframe digital board parts list Model 2520 Pulsed Laser Diode Test System Service Manual Circuit designation Description Keithley part no U38 U49 32 BIT BUS SWITCH HOTSWITCH LSI 260 U4 PROGRAMMED ROM 2520 802B01 U47 LARGE SCALE IC SMT LSI 244 U48 IC QUAD 2 INPUT OR GATES IC 1365 U5 IC GPIB ADAPTER 9914A LSI 123 U50 IC QUAD 2 INPUT NOR GATES IC 1363 U51 U52 IC HEX INVERTER IC 1366 U54 IC 16 BIT MULTIPLYING DAC IC 1359 U55 IC DUAL FET OP AMP IC 1128 U58 IC 8 STAGE SHIFT C074HC409AM IC 1026 U59 IC HEX INVERTER IC 1367 U6 IC OCTAL INTERFACE BUS 75160 IC 646 U60 IC HIGH PRECISION 10V REFERENCE IC 1121 U7 U9 U11 U12 U14 IC HCPL0631 PACK IC 1153 U8 U10 U18 U34 U46 IC POS NAND GATES INVERT 74HCT14 IC 656 VRI DIODE ZENER 30V BZX84C30 DZ 106 30 W1 W4 JUMPER J 24 1 YI CRYSTAL FSM327 CR 41 Y2 OSCILLATOR 30M CR 56 4 Model 2520 Pulsed Laser Diode Test System Service Manual Replaceable Parts 6 9 Table 6 2 Mainframe display board parts list Circuit designation Description Keithley part no C901 CAP 22UF 20 6 3 TANTALUM C 417 22 C902 C904 C907 C90
58. 1 2 Performance Verification Model 2520 Pulsed Laser Diode Test System Service Manual Introduction Use the procedures in this section to verify that Model 2520 Pulsed Laser Diode Test System accuracy is within the limits stated in the instrument s one year accuracy specifications You can perform these verification procedures When you first receive the instrument to make sure that it was not damaged during shipment e To verify that the unit meets factory specifications e To determine if calibration is required Following calibration to make sure it was performed properly Model 2520 Pulsed Laser Diode Test System Service Manual Performance Verification 1 3 WARNING While the Model 2520 does not incorporate a laser it is designed to operate power laser diode devices Read all safety precautions listed at the beginning of the Model 2520 User s Manual The following safety practices must be used to protect operators and other users of this product from potential exposure to laser radiation Operators must be protected from radiation and electrical hazards at all times The installer must comply with all applicable laws and regulations on laser safety This requirement includes warning signs and oper ator training The interlock is required for safe operation The test fixtures must ensure that the interlock circuit is disabled source outputs inhib ited so that an operator is not exposed to any radiation The test fixture
59. 12V 5 Referenced to jumper W3 11 TP23 12V 5 Referenced to jumper W3 12 TP32 3 3V 5 Referenced to jumper W3 Test points TP are marked on circuit boards Model 2520 Pulsed Laser Diode Test System Service Manual Digital circuitry checks Digital circuit problems can be checked out using Table 4 3 See Principles of operation for a digital circuit description 4 14 Troubleshooting Table 4 3 Digital circuitry checks Item Step component 1 Power on test 2 Clip W2 3 U15 pin 7 4 U15 pin 68 5 U15 A0 A18 6 U15 DO D15 7 U15 pin 66 8 U20 pin 7 9 U20 pin 8 10 US pins 34 42 11 US pins 26 31 12 US pin 24 13 US pin 25 14 U15 pin 43 15 U15 pin 44 16 U15 pin 45 17 U15 pin 47 Required condition RAM OK ROM OK Digital common 5V Low on power up then goes high Check for stuck bits Check for stuck bits 16 78MHz Pulse train during RS 232 I O Pulse train during RS 232 I O Pulse train during IEEE 488 I O Pulses during IEEE 488 I O Low with remote enabled Low during interface clear Pulse train Pulse train Pulse train Pulse train Remarks Verify that RAM and ROM are functional All signals referenced to digital common Digital logic supply MPU RESET line MPU address bus MPU data bus MPU clock RS 232 TX line RS 232 RX line TEEE 488 data bus TEEE 488 command lines TEEE 488 REN line TEEE 488 IFC line D_RETURN_DATA D SPI DATA
60. 13 TG 321 Model 2520 Pulsed Laser Diode Test System Service Manual Replaceable Parts 6 13 Table 6 4 Pulse board parts list Circuit designation Description Keithley part no CI CAP 1UF 10 25V CERAMIC C 495 1 C10 C11 C12 C13 CAP 680U 20 50V ALUM ELEC C 578 680 C14 CAP 10U 20 35V TANTALUM C 551 10 C16 C19 C22 C24 C27 C29 CAP 22U 20 25V ALUM ELEC C 609 22 C26 C28 C2 C31 C32 C39 C40 C44 CAP 1UF 20 50V CERAMIC C 418 1 C45 C47 C3 C4 C6 C9 C15 C17 C18 CAP 1UF 20 50V CERAMIC C 418 1 C20 C21 C23 C25 C33 CAP 2200P 1 50V CERAMIC C 532 2200P C34 CAP 150PF 5 100V CERAMIC C 465 150P C35 C36 CAP 270PF 5 100V CERAMIC C 465 270P C37 CAP 33PF 5 100V CERAMIC C 465 33P C38 CAP 47P 5 100V CERAMIC C 465 47P C41 CAP 470U 20 25V ALUM ELEC C 478 470 C42 CAP 2200P 1 50V CERAMIC C 532 2200P C46 CAP 1UF 20 50V CERAMIC C 418 1 C5 CAP 10PF 5 50V MONO CERAMIC C 452 10P CRI SCHOTTKY DIODE RF 121 CR2 CR3 CR4 CR5 CR6 CR7 DIODE SWITCHING MMBD914 RF 83 DS1 DS2 LED GRN LGT679 C0 PL 107 1 HS11 HS12 HEAT SINK HS 51 J1 J2 CONN BNC RIGHT ANGLE PLASTIC CS 506 J3 CONN D SUB MALE BOARDLOCK TYPE CS 848 9 J4 CONN HEADER STRAIGHT SOLDER PIN CS 368 26 J5 LATCHING HEADER FRICTON SGL ROW CS 724 3 K1 K2 K3 FORM 2A2B POLARIZED RELAY S28B 5V RL 207 L1 L2 FERRITE CHIP 600 OHM BLM32A07 CH 62 L3 FERRITE CHIP 600 OHM BLM32A07 CH 62 Ql TRANS P CHAN MMBFJ175 TG 311 Q10 Q11 Q12
61. 1W THICK FILM R 418 226 R162 R166 RES 10K 1 100MW THICK FILM R 418 10K R168 R170 R200 R202 R206 R219 RES 10K 1 100MW THICK FILM R 418 10K R220 R233 R17 R18 R19 R20 R32 RES 475 1 1 4W METAL FILM R 391 475 R176 R179 R207 R210 R221 R224 RES 909 1 1W THIN FILM R 438 909 R180 R181 R211 R212 R225 R226 RES 71 5 1 100MW THICK FILM R 418 71 5 R182 R184 R213 R215 R227 R229 RES 604 1 1W THIN FILM R 438 604 R185 R218 R235 RES 2K 1 100MW THICK FILM R 418 2K R189 R192 R195 R196 RES 5 11K 1 100MW THICK FILM R 418 5 11K R216 R217 R230 RES 715 1 100MW THIN FILM R 438 715 R23 R26 R28 RES 100 1 1 4W METAL FILM R 391 100 R231 R193 R194 R197 R199 R201 RES 49 9 1 100MW THICK FILM R 418 49 9 R232 R236 R171 R174 R186 R188 RES 100 1 100MW THICK FILM R 418 100 R234 R121 R141 R145 R148 R151 RES 10K 1 100MW THICK FILM R 418 10K R153 R157 R237 R242 RES 49 9 1 1 4W METAL FILM R 391 49 9 R24 R25 R27 R33 RES 226 1 1W THICK FILM R 418 226 R29 R49 R54 R56 R75 R80 R104 RES 100 1 100MW THICK FILM R 418 100 R3 R46 R48 RES 2K 1 100MW THICK FILM R 418 2K R30 RES 332 10 1 4W METAL FILM R 391 332 R31 RES 150 1 100MW THICK FILM R 418 150 R4 RES 332K 1 100MW THICK FILM R 418 332K R41 R43 RES 4 75K 1 100MW THICK FILM R 418 4 75K R42 R44 RES 249 1 100MW THICK FILM R 418 249 R45 R47 RES 221 1 100MW THICK FILM R 418 221 R5 RES 10M 1 125MW THICK FILM R 418 10M R57
62. 2 C55 C56 CAP 1000PF 10 50V MONO CERAMIC _ C 452 1000P C6 CAP 470U 20 25V ALUM ELEC C 557 470 C69 C73 CAPACITOR C 606 470 C8 C115 C156 C161 C162 CAP 1UF 10 25V CERAMIC C 495 1 C86 C88 C92 C97 C99 C11 CAP 1UF 20 50V CERAMIC C 418 1 C12 C18 C23 C29 CR1 CR2 DIODE SWITCHING MMBD914 RF 83 CR13 CR14 CR17 CR18 DIODE DUAL SWITCHING BAV99L RF 82 CR25 CR30 CR15 CR16 DIODE SCHOTTKY BARRIER 50V BAS86 RF 129 CR19 CR23 DIODE DUAL COMMON ANODE RF 98 BAWS6LT2 CR24 DIODE MBR5130LT3 RF 115 CR3 CR4 CR8 CRI11 ULTRAFAST POWER RECTIFIER RF 105 CR5 CR6 ULTRAFAST POWER RECTIFIER RF 107 Model 2520 Pulsed Laser Diode Test System Service Manual Replaceable Parts 6 5 Table 6 1 continued Mainframe digital board parts list Circuit designation Description Keithley part no CR7 CR12 ULTRA FAST BRIDGE RECTIFIER RF 123 EDFIBM Fl POLYSWITCH SMD030 2 FU 103 FOR CS 501 4 40X5 16 PHILLIPS PAN HD 4 40X5 16PPH HS1 HS2 HS21 HS26 HEAT SINK HS 55 J1003 CONN MINI D RIBBON 26 PINS CS 1105 26 J1004 CONN CIRCULAR DIN CS 762 J1005 CONN D SUB DUAL STACK M F CS 1072 1 J1006 J1034 LATCHING HEADER FRICTON SGL ROW CS 724 3 J1007 CONN HEADER 36 PINS CS 368 36 J1008 CONN RIGHT ANGLE 24 PIN CS 501 J1009 CONN HEADER STRAIGHT SOLDER PIN CS 368 10 J1010 CONN DUAL 7 PIN BERG CS 389 5 J1011 CONN MALE 4 PIN CS 288 4 J1012 CONN BERG CS 339 J1033 CONN HEADER STRAIGHT SOLDER PIN CS 368 16 L1 L3 L16 L18
63. 2 CAP 1UF 20 50V CERAMIC C 418 1 C224 C226 C228 C218 C221 C223 C279 C281 CAP 01uF 20 50V CERAMIC C 418 01 C283 C286 C227 C229 C230 C292 C294 CAP 100P 10 100V CERAMIC C 451 100P C232 C236 C191 C192 C194 CAP 1UF 20 50V CERAMIC C 418 1 C196 C199 6 4 Replaceable Parts Model 2520 Pulsed Laser Diode Test System Service Manual Table 6 1 continued Mainframe digital board parts list Circuit designation Description Keithley part no C237 CAP 1000P 10 100V CERAMIC C 451 1000P C239 C263 C287 CAP 47P 596 100V CERAMIC C 465 47P C240 C245 C250 C253 C262 CAP 1UF 20 50V CERAMIC C 418 1 C264 C278 C282 C246 C247 C249 C251 C252 CAP 220PF 10 100V CERAMIC C 451 220P C25 C41 CAP 15P 1 100V CERAMIC C 512 15P C26 C114 C155 C157 CAP 470U 20 25V ALUM ELEC C 478 470 C27 CAP 100P 10 100V CERAMIC C 451 100P C280 CAP 47PF 10 100V CERAMIC C 451 47P C288 C291 C295 C300 C307 CAP 1UF 2096 50V CERAMIC C 418 1 C308 C238 C301 C306 C193 C195 C197 C198 CAP 01uF 2096 50V CERAMIC C 418 01 C200 C201 C31 C66 C68 C70 C74 C77 C81 CAP 22U 20 25V ALUM ELEC C 609 22 C32 C37 C38 C40 C50 C54 C59 CAP 1UF 20 50V CERAMIC C 418 1 C312 C320 C33 C35 C36 C57 C58 C61 C62 CAP 47U 20 50V ALUM C 579 47 C71 C75 C34 CAP 470U 20 50V ALUM ELEC C 570 470 C39 CAP 47PF 10 100V CERAMIC C 451 47P C4 C9 C24 CAP 22UF 20 25V TANTALUM C 440 2
64. 20 Pulsed Laser Diode Test System Service Manual Calibration 2 5 Calibration cycle Perform calibration at least once a year to ensure the unit meets or exceeds its specifications Recommended calibration equipment Table 2 1 lists the recommended equipment for the calibration procedures You can use alternate equipment as long that equipment has specifications at least as good as those listed in the table For optimum calibration accuracy test equipment specifications should be at least four times better than corresponding Model 2520 specifications Table 2 1 Recommended calibration equipment Description Manufacturer Model Specifications Calibrator Fluke 5700A DC Voltage 5V 5ppm 10V 5ppm Digital Keithley 2001 DC Voltage 20V 22ppm Multimeter DC Current 2mA 320ppm 20mA 320ppm 200mA 320ppm Resistance 200 59ppm 200Q 43ppm 2KQ 37ppm Resistors 1 2 to 1 60 2W 5 Temperature 4 coefficient gn Sa ke 1000 0 5W 1 all resistors 200Q 2W 1 400Q 1W 1 1kQ 0 5W 1 2kQ 0 25W 1 1 90 day accuracy specifications of lowest usable range for specified output 2 90 day full range accuracy specifications 3 Characterize resistors to within 100ppm using 4 wire ohms function of digital multimeter before use 4 Use only non inductive metal film or bulk metal resistors Resistor characterization The precision resistors listed in Table 2 1 should be characterized to within 10
65. 2520 Testhead Model 2001 DMM Inner Shield eme Kar Sum Triax Cable Conductor Input LO DETECTOR 1 DETECTOR 2 Calibration 2 2 Calibration Model 2520 Pulsed Laser Diode Test System Service Manual Introduction Use the procedures in this section to calibrate the Model 2520 Pulsed Laser Diode Test System These procedures require accurate test equipment to supply and measure precise DC currents and voltages Calibration can be performed either from the front panel or by sending SCPI calibration commands over the IEEE 488 bus or RS 232 port with the aid of a computer Model 2520 Pulsed Laser Diode Test System Service Manual Calibration 2 3 WARNING While the Model 2520 does not incorporate a laser it is designed to operate power laser diode devices Read all safety precautions listed at the beginning of the Model 2520 User s Manual The following safety practices must be used to protect operators and other users of this product from potential exposure to laser radiation Operators must be protected from radiation and electrical hazards at all times The installer must comply with all applicable laws and regulations on laser safety This requirement includes warning signs and oper ator training The interlock is required for safe operation The test fixtures must ensure that the interlock circuit is disabled source outputs inhib ited so that an operator is not exposed to an
66. 5 L eg E A 2215 29 ES De gt lt Ge 205k a St B B e Li c 2 E 2 mmm mmm S 2 LUNN s n e S m m PR S gt e ca F S kr ul O SEIT 3 p 2 Ka s zu O yin TES AAA yN cl ea lt L T r S Es NS el E T o EX m Si Ot M A mE od Og gt us seed Ea d Fi zt d IW DI o az O cr zx 523 An 97H Se EZ 22 EZ 2 S c5 m E E ES co Tn g E ES E MIN 2118 ETTA gt K cie3 de 55 E Be pea ut oo oo DT OC Ka Ss 22008 sug umm mem MEE a SS BE UM i onions SEIT em a E NW EE Es x 1 E oza e ess B B B B B Um D oppo N r o oe 2 2 B B B B B B EB pR np BIBBI amp p o E E Q P a ODDO gt Li acto HS ENE e ES ala 000000000 SE 3 or BE 918 er 3 Es E cse DE EM A 222000000 C ay o FEE HS 00000000 gt 70000000 a k a seit OG A m p m Fy 2 a8 TE Peni KOTA Get MN al 5 o R Sek EE j a C5 1 IN tT I Ga Eo t e 2 2 OTOTr ac quon 000 C ES Li 3 E N 135351330 EE S UM RE ES XXX X XXX E m 3002 Uva S H ae a c COUO00000003 S nun i4 Far ees A S 7 in E 3 eo S oo Spy alsanasa 1 ca x Pi S Bt Deor E Z 3 8 OD 1014 st Sa x N DDODDODU Joota CY on x Be Deen P O 2 DUO 968 o O 68 LA eco 7 mos T 964 Re E Sa 7 Leo gt x STI Te DL 69 o O C E OO ros s 2 zi eu O 684 Led US O Oo Es 7 E e E i i D c gt a o gt SC a e oF GN cl S O n d Ca 2 3 at el pars na 1 x S o y Va E
67. 8 C910 CAP 1UF 20 100V CERAMIC C 436 1 C903 C905 C906 C909 C911 CAP 1UF 20 50V CERAMIC C 418 1 C912 CAP 2 2UF 20 100V ALUM ELEC C 503 2 2 C913 C914 CAP 100UF 20 16V TANTALUM C 504 100 C915 C916 CAP 33PF 10 100V CERAMIC C 451 33P CR901 CR902 CR903 CR904 DIODE SWITCHING 250MA BAV103 RF 89 CR905 CR906 DIODE SWITCHING MMBD914 RF 83 DS901 VACUUM FLUORESCENT DISPLAY DD 51C J1032 CONN BERG CS 339 J1033 CONN HEADER STRAIGHT SOLDER PIN CS 368 16 Q901 Q902 TRANS NPN GEN PURPOSE BC868 TG 293 R901 RES NET 15K 2 1 875W TF 219 15K R902 RES 13K 5 125MW METAL FILM R 375 13K R903 R904 RES 4 7K 5 250MW METAL FILM R 376 4 7K R905 RES 1M 5 125MW METAL FILM R 375 1M R906 RES 1K 5 250MW METAL FILM R 376 1K R907 RES 240 5 250MW METAL FILM R 376 240 R908 RES 10M 5 125MW METAL FILM R 375 10M T901 TRANSFORMER TDK ER14 5 SERIES TR 300 U901 U904 U905 IC LATCHED DRIVERS UCN 5812EPF 1 IC 732 U902 PROGRAMMED ROM 7001 800A02 U903 IC 32 BIT SERIAL UCN5818EPF 1 IC 830 VR901 DIODE ZENER 8 2V MMBZ5237 DZ 92 Y901 CRYSTAL 4MHZ CR 36 4M 6 10 Replaceable Parts Model 2520 Pulsed Laser Diode Test System Service Manual Table 6 3 Test head board parts list Circuit designation Description Keithley part no C1 C52 C53 C59 C60 C2 CAP 470UF 20 63V ALUM ELEC C 477 470 C11 C13 C17 C18 C29 C30 C33 CAP 22U 20 25V ALUM ELEC C 609 22 C34 C46 C49 C12 C22 CAP 68PF 10 100V
68. A 1 MOUNTING EAR LEFT 428 338B 1 MOUNTING EAR RIGHT 428 328E 1 PCB SUPPORT 2520 329A 1 POWER SUPPLY PS 41C 1 PRINTED FRONT PANEL 2520 306A 1 PRINTED FRONT PANEL V 2520 306A Model 2520 Pulsed Laser Diode Test System Service Manual Table 6 5 continued Miscellaneous parts list Replaceable Parts 6 17 Qty Description Keithley part no 1 REAR PANEL 2520 303A 1 SAFETY COVER MODIFIED 2520 330A 1 SWITCH SW 513A 1 SWITCH SW 513A 2 TRIAX CABLE CA 289 1A CO O E GA E o n o A L e m a 1 m LL DO LO 78 m O il E X un Ld Pra SEA zu SS pl aca VE Lid TIO Lu Lu y E oO gt nu OD 2 EM S TO a E ES x oc Cos ze E Lu os NED CN O a LC z Sc S gt me p C2 E a A ZN a O e Lu O A ee Z Be Lil C E ro xu LC 2 S Lu Ly E UL I Cr 1 S VS a a a Ee SCH 1 a Ll x c A c ec KS ES lt x a E u a 72 C lt t besi O ZA C Ly D 1 lt LG h C B D NOT
69. A Range CURRENT OUTPUT LO CURRENT OUTPUT HI VOLTAGE VOLTAGE SENSEHI SENSE L 2 14 Calibration Model 2520 Pulsed Laser Diode Test System Service Manual Step 4 Pulse low calibration Follow the steps below to calibrate current source pulse low Table 2 6 summarizes cali bration currents and test resistance values 1 Connect DMM and 100Q resistor to the Model 2520 testhead CURRENT OUTPUT jacks as shown in Figure 2 4 2 Select the DMM DC volts function and enable auto range 3 Press the LASER I key press the EDIT key then set the source to the 500mA range using the RANGE y key 4 Press the MENU key select CAL then press ENTER 5 Select EXECUTE then press ENTER to enter the calibration menu 6 Select PULS LOW then press ENTER The unit displays Pulse Low CAL Press ENTER to Output 15 000mA 7 Press ENTER The unit displays DMM RDG 15 000mA Use lt gt A V ENTER or EXIT 8 Note the DMM voltage reading then calculate the current from the voltage and actual resistance value I V R 9 Adjust the display to agree with the calculated current then press ENTER The unit displays Pulse Low CAL Press ENTER to Output 01 500mA 10 Press ENTER The unit displays DMM RDG 01 500mA Use d gt A V ENTER or EXIT 11 Again note the DMM voltage reading then calculate the current from the voltage and actual resistance value I V R Table 2 6 Pulse low calibration values Current source range
70. AVE LOCK CHAN GE PASSWO RD Select UNLOCK then enter the password Default 002520 3 Select CHANGE PASSWORD and then press ENTER The instrument will dis play the following New Pwd 002520 Use 4 gt A Y ENTER or EXIT Using the EDIT keys enter the new password on the display 5 Once the desired password is displayed press the ENTER key to store the new password Changing the password by remote To change the calibration password by remote first send the present password and then send the new password For example the following command sequence changes the pass word from the KI002520 remote default to KICAL CAL PROT CODE KI002520 CAL PROT CODE KICAL You can use any combination of letters and numbers up to a maximum of eight characters NOTE Ifyou change the first two characters of the password to something other than KT you will not be able to unlock calibration from the front panel Resetting the calibration password If you lose the calibration password you can unlock calibration by shorting together the CAL pads which are located on the display board Doing so will also reset the password to the factory default 002520 front panel KI002520 remote See Section 5 for details on disassembling the unit to access the CAL pads Refer to the display board component layout drawing at the end of Section 6 for the location of the CAL pads Model 2520 Pulsed Laser Diode Test System Service Manu
71. CLAMP 3 REQ D PART NUMBER QTY DESCRIPTION R r 2520 004 CRIMP ASSEMBLY d 2520 3028 CHASSIS 6 32KEPNUT 10 IN LBS 2520 3294 BRACKET GRN YEL FROM MODULE CA 266 18 CABLE Q e ET 3 CABLE CLAMP CS 15 CONNECTOR EG gt FOOT 2520 302B CHASSIS FH 39 FUSE HOLDER FU 106 1 6 FUSE 1 6 AMP gt PM 6 1 POWER MODULE TR Sm SEE DETAIL A LU 100 4 40X5 IGPFH PM 6 POWER MODULE 2 REQ D 5 IN LBS PS 41C POWER SUPPLY M2 5X8PPH 2 METRIC PHIL PAN HEAD SCREW 428 3194 FOOT 2 REQ D EET e FU 106 1 6 FUSE VU un x Wei Pe 2 REQ D 8 IN LBS 2520 2520 051 Ee ebe ERE 40X1 L PAN HEAD SCREW FE 6 FOOT 2 REQ D MODEL NEXT ASSEMBLY NEXT PROCESS STEP QTY 4 40KEPNUT 2 KEPNUT 7 DIMENSIONAL TOLERANCES DO NOT SCALE THIS DRAWING s 428 3194 2 FOOT UNLESS OTHERWISE SPECIFIED serer FT de 6 32X1 4PFH 2 PHIL FLAT HEAD SCREW XX 5 015 ANG f CC 38 2 CABLE TIE KEIT ILEY Keithley Instruments Inc XXX 4 005 FRAC 41 64 FE 12 FOOT Cleveland Ohio 44139 Se 2520 050 2520 3304 SAFETY COVER SURFACE MAX 7
72. CLS will also clear the error queue and operation complete status Generating an SRQ on calibration complete An IEEE 488 bus SRQ service request can be used to detect operation complete instead of repeatedly polling the Model 2520 To use this method send both ESE 1 and SRE 32 to the instrument then include the OPC command at the end of each calibration com mand line as covered above Clear the SRQ by querying the ESR using the ESR query to clear OPC status then request the status byte with the STB query Refer to your controller s documentation for information on detecting and servicing SRQs Index Aborting calibration steps 2 9 Assembly drawings 5 3 Calibration 2 1 Calibration commands B 2 Calibration considerations 2 4 Calibration cycle 2 5 Recommended calibration equipment 2 5 Resistor characterization 2 5 Calibration errors 2 9 B 9 Front panel error reporting 2 9 Remote error reporting 2 9 Calibration menus 2 6 Calibration Reference B 1 Case cover removal 5 4 Changing the password 2 8 by remote 2 8 from the front panel 2 8 Command summary B 2 Component layouts 6 2 Current measurement accuracy 1 11 Current source accuracy 1 10 Current source commands B 7 DATA B 7 LOW B 8 PROTection B 7 SOURce B 7 Detecting calibration errors B 9 Error summary B 9 Generating an SRQ on error B 10 Reading the error queue B 9 Status byte EAV Error Available bit B 10 Detecting calibration step complet
73. CURR LOW 1 5e 3 CAL PROT SOUR1 LOW Current 754A OUTP1 OFF SA 10Q OUTP1 ON SOUR 1 PULS TRAN STAT OFF ON SOUR 1 CURR RANG 5 SOUR 1 CURR LOW 150e 3 CAL PROT SOUR1 LOW Current 900uA gt SOURI CURR LOW 15e 3 CAL PROT SOUR1 LOW Current 750uwA gt OUTP1 OFF 1 Use actual resistance values when calculating currents 2 Repeat steps for both fast and slow pulses See procedure 2 30 Calibration Model 2520 Pulsed Laser Diode Test System Service Manual Step 5 Voltage bias source calibration Follow these steps to calibrate the two voltage bias sources Table 2 12 summarizes cali bration voltages and commands 1 10 11 12 13 Connect the DMM to the Model 2520 testhead DETECTOR 1 and VOLTAGE SENSE HI jacks as shown in Figure 2 5 Select the DMM DC voltage function and enable auto range Connect the VOLTAGE SENSE HI terminal to internal ground DIAG KEIT FCON HION Send this command to turn on the output OUTP1 ON Send the following command to output 20V SO U R2 VOLT 20 Note and record the DMM reading and then send the negative of that value as the parameter for the following command CAL PROT SO UR2 lt DMM Reading Send the following command to output OV SOU R2 VOLT 0 Note and record the DMM reading and then send the negative of that value as the parameter for the following command CAL PRO T SO U R2 lt DMM_Reading gt Send the following comm
74. Calculate the current from the DMM voltage reading and characterized resistance value I V R 10 Calculate reading limits based on the current and Model 2520 specifications then verify that the Model 2520 DETECTOR 1 current reading is within the limits 11 Repeat steps 5 through 10 for the 20mA 50mA and 100mA ranges Be sure to use the correct test resistor for each range 12 After verifying all ranges for DETECTOR 1 repeat the entire procedure for DETECTOR 2 Connect the calibrator to the TESTHEAD DETECTOR 2 jack and select that channel by pressing DETECTOR 2 Ipp See Figure 1 5 for connections Table 1 4 Current measurement verification limits Model 2520 Reading limits range Test resistor 1 year 18 C to 28 C 10mA 2KQ 9 950 to 10 050mA 20mA 1kQ 19 875 to 20 125mA 50mA 4000 49 760 to 50 240mA 100mA 200Q 99 53 to 100 47mA Nominal values Recalculate limits from characterized resistance and measured voltage I V R Model 2520 Pulsed Laser Diode Test System Service Manual Performance Verification 1 13 Figure 1 5 Connections for DETECTOR 2 current measurement verification tests Center Input HI Conductor Model 2001 DMM H M odel 2520 Testhead 290000000 2 j o lt D D CD Y c l aeos mem SE ER e CS Inner e Shield Pus al ae Resistor npu p See Text DETECTOR 2 Voltage bias source accuracy Follow the steps below to ve
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76. EG CAL PROT SENS1 10 DIAG KEIT FCON LO OFF Polarity reversed by switching calibrator connections See procedure 2 26 Calibration Model 2520 Pulsed Laser Diode Test System Service Manual Step 3 Current source calibration Follow these steps to calibrate the current source Table 2 10 summarizes current source calibration resistances and commands 1 10 11 12 13 14 15 Send the following command to select the pulse mode SOUR1 FUNC SHAP PULS Send the following commands to set source and measure polarities SEN S1 VOLT POL POS SOUR1 CURR POL POS Connect the 10 to 15Q resistor to the Model 2520 testhead VOLTAGE SENSE and CURRENT OUTPUT jacks as shown in Figure 2 3 Set the pulse transition to fast SOUR1 PULS TRAN STAT OFF Set ranges with these commands SENS1 VOLT RANG 10 SOUR1 CURR RANG 0 5 Send this command to turn on the source output OUTP1 ON Set the compliance DAC to full scale so that it does not affect the measurement DIAG KEIT BITS VD AC1 4095 Source 10 of full scale SO UR1 CURR 0 05 Trigger a pulse INIT Send the following query to request the Model 2520 voltage measurement SENS1 DATA Note the voltage reading returned by the Model 2520 in step 10 then calculate the actual sourced current as follows I V R Here I is the actual sourced current V is the returned Model 2520 voltage reading and R is the actual resistance value Send the followi
77. EMS TO AUDIT BAG FROM 2520 300 ASSEMBLY PART NUMBER QTY DESCRIPTION 2520 052 CHASSIS ASSEMBLY EE Fn PO 14 4 CHIPLOC BAG PER MS 1537 TO IEC UNIT IS TO BE SHIPPED WITH CO 7 LINE CORD W O SHIPPING KIT GREEN MASK ON THE LENS DC VOLTAGE SPEC 2520 900 00 MANUAL PACKAGE W O SHIPPING KIT zc AA AAA CERTIFICATE OF CALIBRATION PA 214 PRINTED IN PRODUCTION 428 329F HANDLE CALL STOCKROOM FOR WORK ORDER SHIPPING KIT BEFORE SENDING TO F G S 2520 Audit Audit CA 289 1A CABLE W 0 SHIPPING KIT MODEL NEXT ASSEMBLY NEXT PROCESS STEP QTY CA 290 18 CABLE W O SHIPPING KIT Vi USED ON PA 795A PACKING LIST W O SHIPPING KIT S E TI RST A PA 796A PACKING LIST W O SHIPPING KIT DO NOT SCALE THIS DRAWING UNLESS OTHERWISE SPECIFIED DATE 24 Oct 00 SCALE OE ENG Final Inspection PA T9TA PACKING LIST W O SHIPPING KIT XX 015 ANG f DRN Lg APPR LS PA 198A PACKING LIST W O SHIPPING KIT KI I ILEY Keithley Instruments Inc XXX 4 005 FRAC 41 64 MATERIAL NO C 0 44 39 E ale GE I 2520 903 00 MANUAL PACKAGE W O SHIPPING KIT Eer SER 7 STERN H 2520 080 SURFACE MAX 6 Replaceable Parts 6 2 Replaceable Parts Model 2520 Pulsed Laser Diode Test System Service Manual Introduction This section con
78. ESSED OR IMPLIED INCLUD ING ANY IMPLIED WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR USE THE REMEDIES PROVIDED HEREIN ARE BUYER S SOLE AND EXCLUSIVE REMEDIES NEITHER KEITHLEY INSTRUMENTS INC NOR ANY OF ITS EMPLOYEES SHALL BE LIABLE FOR ANY DIRECT INDIRECT SPECIAL INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THE USE OF ITS INSTRUMENTS AND SOFTWARE EVEN IF KEITHLEY INSTRUMENTS INC HAS BEEN ADVISED IN ADVANCE OF THE POSSIBILITY OF SUCH DAMAGES SUCH EXCLUDED DAM AGES SHALL INCLUDE BUT ARE NOT LIMITED TO COSTS OF REMOVAL AND INSTALLATION LOSSES SUSTAINED AS THE RESULT OF INJURY TO ANY PERSON OR DAMAGE TO PROPERTY KEITHLEY Keithley Instruments Inc 28775 Aurora Road Cleveland OH 44139 e 440 248 0400 Fax 440 248 6168 http www keithley com BELGIUM Keithley Instruments B V Bergensesteenweg 709 B 1600 Sint Pieters Leeuw 02 363 00 40 Fax 02 363 00 64 CHINA Keithley Instruments China Yuan Chen Xin Building Room 705 12 Yumin Road Dewai Madian Beijing 100029 8610 62022886 Fax 8610 62022892 FRANCE Keithley Instruments Sarl 3 all e des Garays 91127 Palaiseau Cedex 01 64 53 20 20 Fax 01 60 11 77 26 GERMANY Keithley Instruments GmbH Landsberger Strasse 65 82110 Germering 089 84 93 07 40 Fax 089 84 93 07 34 GREAT BRITAIN Keithley Instruments Ltd Unit 2 Commerce Park Brunel Road Theale Reading Berkshire RG7 4AB 0118 929 7500 Fax 0118 929 7519 INDIA Keithley Instrume
79. HEXFET POWER MOSFET N TG 409 Q13 014 016 019 Q24 TRANS CURR REG CDLL5313 TG 321 Q18 Q21 Q22 TRANS NPN MMBT3904 TG 238 Q2 Q3 Q4 TRANS N MOSFET VN0605T TG 243 Q25 Q26 Q27 TRANS PNP COMP SILICON AMP TG 158 MPS8599 6 14 Replaceable Parts Table 6 4 continued Pulse board parts list Model 2520 Pulsed Laser Diode Test System Service Manual Circuit designation Description Keithley part no Q5 06 07 08 017 Q20 Q23 TRANS PNP MMBT3906L TG 244 Q9 TRANS HEXFET POWER MOSFET TG 304 RI RES 2 5 1 1 5W METAL FOIL R 501 2 5 R10 RES 22 1K 1 100MW THICK FILM R 418 22 1K R11 R9 R51 RES 10K 1 100MW THICK FILM R 418 10K R12 R20 RES 475 1 100MW THICK FILM R 418 475 R15 RES 24 9 1 100MW THICK FILM R 418 24 9 R16 R21 R14 RES 324 1 100MW THIN FILM R 438 324 R2 RES 215 1 100MW THICK FILM R 418 215 R22 R13 RES 38 3K 1 100MW THIN FILM R 438 38 3K R24 RES 11 8K 1 100MW THIN FILM R 438 11 8K R25 RES 43 2 1 100MW THICK FILM R 418 43 2 R26 RES 2K 1 100MW THICK FILM R 418 2K R27 RES 24 9 1 100MW THICK FILM R 418 24 9 R28 R30 RES 200 1 100MW THICK FILM R 418 200 R29 R53 R59 R63 RES 2 2 5 1W THICK FILM R 500 2 2 R3 R6 R7 R17 R19 R48 R67 R68 RES IK 1 100MW THICK FILM R 418 1K R33 R35 RES 33 5 250MW METAL FILM R 376 33 R34 R36 R32 RES 33 5 250MW METAL FILM R 376 33 R37 R40 R31 RES 20 1 100MW THICK FILM R 418 20 R38 R39 R41 R42 RESISTOR R 509 2 2
80. If the front panel display tests indicate that there is a problem on the display board use Table 4 1 See Principles of operation for display circuit theory Table 4 1 Display board checks Item Step component Required condition Remarks 1 Front panel test Verify that all segments operate Use front panel display test J1033 5V 5 Digital 5V supply 3 U902 pin I Goes low briefly on power up and Microcontroller RESET then goes high 4 U902 pin 43 4MHz square wave Controller 4MHz clock 5 U902 pin32 Pulse train every ms Control from main processor 6 U902 pin 33 Brief pulse train when front panel key Key down data sent to main processor is pressed Model 2520 Pulsed Laser Diode Test System Service Manual Troubleshooting 4 13 Power supply checks Power supply problems can be checked out using Table 4 2 See Principles of operation for circuit theory on the power supply Table 4 2 Power supply checks Item Step component Required condition Remarks 1 Line fuse Check continuity Remove to check 2 Line power Plugged into live receptacle power on Check for correct power up sequence 3 TP1 25V 10 Referenced to jumper W3 4 TP2 25V 10 Referenced to jumper W3 5 TP14 25V 5 Referenced to jumper W3 6 TP15 12V 5 Referenced to jumper W3 7 TP16 5V 5 Referenced to jumper W3 8 TP20 5V 5 Referenced to jumper W3 9 TP21 5V 5 Referenced to jumper W3 10 TP22
81. Instruments Taiwan Copyright 2000 Keithley Instruments Inc Printed in the U S A 28775 Aurora Road Cleveland Ohio 44139 440 248 0400 Fax 440 248 6168 1 888 KEITHLEY 534 8453 www keithley com Bergensesteenweg 709 B 1600 Sint Pieters Leeuw 02 363 00 40 Fax 02 363 00 64 Yuan Chen Xin Building Room 705 12 Yumin Road Dewai Madian Beijing 100029 8610 6202 2886 Fax 8610 6202 2892 3 all e des Garays 91127 Palaiseau C dex 01 64 53 20 20 Fax 01 60 11 77 26 Landsberger Strasse 65 D 82110 Germering 089 84 93 07 40 Fax 089 84 93 07 34 Unit 2 Commerce Park Brunel Road Theale Reading Berkshire RG7 4AB 0118 929 7500 Fax 0118 929 7519 Flat 2B WILLOCRISSA 14 Rest House Crescent Bangalore 560 001 91 80 509 1320 21 Fax 91 80 509 1322 Viale San Gimignano 38 20146 Milano 02 48 39 16 01 Fax 02 48 30 22 74 2FL URI Building 2 14 Yangjae Dong Seocho Gu Seoul 137 130 82 2 574 7778 Fax 82 2 574 7838 Postbus 559 e NL 4200 AN Gorinchem 0183 635333 Fax 0183 630821 Kriesbachstrasse 4 8600 D bendorf 01 821 94 44 Fax 01 820 30 81 1FL 85 Po Ai Street Hsinchu Taiwan R O C 886 3 572 9077 Fax 886 3 572 9031 No 2193 4 2001
82. KEITHLEY Model 2520 Pulsed Laser D iode T est System Service Manual TEquipment An Interworld Highway LLC NET A GREER MEASUR SOME ONFIDENCE WARRANTY Keithley Instruments Inc warrants this product to be free from defects in material and workmanship for a period of year from date of shipment Keithley Instruments Inc warrants the following items for 90 days from the date of shipment probes cables rechargeable batteries diskettes and documentation During the warranty period we will at our option either repair or replace any product that proves to be defective To exercise this warranty write or call your local Keithley representative or contact Keithley headquarters in Cleveland Ohio You will be given prompt assistance and return instructions Send the product transportation prepaid to the indicated service facility Repairs will be made and the product returned transportation prepaid Repaired or replaced products are warranted for the balance of the original warranty period or at least 90 days LIMITATION OF WARRANTY This warranty does not apply to defects resulting from product modification without Keithley s express written consent or misuse of any product or part This warranty also does not apply to fuses software non rechargeable batteries damage from battery leakage or problems arising from normal wear or failure to follow instructions THIS WARRANTY IS IN LIEU OF ALL OTHER WARRANTIES EXPR
83. MS SES DN SER GPS FEIET UJJ M6 Va Ee N R25 So c3 R45 1 Ar E o c8 O E a LJ 3 ei C18 oo R68 per
84. N IN UNLESS NOTED Co Lu We BITE Ee TOL UNLESS OTHER SPECIFIED CO JJ ASSEMBLY o c Su K Ld es e o c3 Ss i Tat e I QU O iii A Ss ew x Se Ss C Em SI GE RS gt M 5 Ime 2 olo O ae SG S w rd gt 7 LJ gt gt Lil e a ue I EN A Ex EE co wo gt lt gt c y Lu NI E E os ET ES Za Es Ld Lid av ay cS I Zz p Ow o 7 zZ V ce a n O LO WESS ms A a S e E i S J De p Sr EE Lud OD gt e oc lt I ac ee e gt os Ld aZ lt L I S e L o yf Ld E 4a Deel o nz oO c 1 To a n Ka en sm S Ey Li Lo A T gt S E uj O oe uy Ly Dal Lu nu O P S z a LEY TAR CN on Ora a S R cme gt a ENG S oc ina Lud uy a ae O ES Lil SCH EE 2 T n a Pu Oo r go a i Lo T nr A tad ES x p O CO c Ex ei SC st o c O Ed LC OD c CJ aa S EC O Em L mn S ON a v d Li ES i E gt E Cr P e a Lu LL gt y DATE DRN NOTED a Se M10 M9 ISE SPEC TE LED D G Y tc ap MEM GE ES Di x W mm o ec Nes a i XXXXXXX E A N Ze AA e JENS BC 3009 3v9 Q 1
85. N SENS2 CURR RANG 10e 3 SOUR1 FUNC SHAP DC SENSE2 CURR POL POS SOUR2 VOLT 20 10mA CAL PROT SENS2 lt Current gt SOUR2 VOLT 0 OmA CAL PROT SENS2 lt Current gt SENSE2 CURR POL NEG OmA CAL PROT SENS2 lt Current gt SOUR2 VOLT 20 10mA CAL PROT SENS2 lt Current gt 20mA 1kQ SENS2 CURR RANG 20e 3 SOUR1 FUNC SHAP DC SENSE2 CURR POL POS SOUR2 VOLT 20 20mA CAL PROT SENS2 lt Current gt SOUR2 VOLT 0 OmA CAL PROT SENS2 lt Current gt SENSE2 CURR POL NEG OmA CAL PROT SENS2 lt Current gt SOUR2 VOLT 20 20mA CAL PROT SENS2 lt Current gt 50mA 40090 SENS2 CURR RANG 50e 3 SOUR1 FUNC SHAP DC SENSE2 CURR POL POS SOUR2 VOLT 20 50mA CAL PROT SENS2 lt Current gt SOUR2 VOLT 0 OmA CAL PROT SENS2 lt Current gt SENSE2 CURR POL NEG OmA CAL PROT SENS2 lt Current gt SOUR2 VOLT 20 50mA CAL PROT SENS2 lt Current gt Nominal values shown Calculate actual current from characterized resistance and DMM voltage reading I V R 2 34 Calibration Model 2520 Pulsed Laser Diode Test System Service Manual Table 2 13 continued Remote current measurement calibration currents and commands Calibration Channel Current range Test resistor currents Calibration commands Detector 1 100mA 2002 SENS2 CURR RANG 100e 3 SOUR1 FUNC SHAP DC SENSE2 CURR POL POS SOUR2 VOLT 20 100mA CAL PROT SENS2 lt Current gt SOUR2 VOLT 0 OmA CAL PROT
86. OMPARATOR LM311M IC 776 U16 U3 IC TINYLOGIC CMOS INVERTER IC 1282 U17 IC 5V REFERENCE SOIC8 IC 1050 U18 U8 IC 1000V OPAMP LT1363CS8 IC 1279 U21 IC VOLTAGE REFERENCE SOIC8 IC 1065 U4 U20 IC DUAL FET OPAMP IC 1128 U5 IC SWITCHED INPUT OPAMP IC 1439 U7 IC QUAD SPST CMOS SWITCH IC 1285 MAX4545CWP U9 IC DUAL D TYPE F F 74HC74 IC 773 6 16 Replaceable Parts Model 2520 Pulsed Laser Diode Test System Service Manual Table 6 5 Miscellaneous parts list Qty Description Keithley part no 1 AC ON OFF LINE SWITCH PM 6 1 1 BEZEL REAR 428 303D 4 CABLE ASSEMBLY BNC CA 290 1B 1 CHASSIS 2520 301B 1 CHASSIS ASSEMBLY 2520 302B 1 CONDUCTIVE RUBBER SWITCH 2520 315A 1 CONN FEMALE 3 PIN SHAPELESS CS 287 3 2 CONN FEMALE 4 PIN SHAPELESS CS 287 4 4 CONNECTOR CS 236 10 CONNECTOR CS 276 6 CONNECTOR CS 236 1 CONNECTOR FEMALE CS 938 1 CONNECTOR HARDWARE KIT CS 713 2 CONNECTOR HOUSING CS 638 3 1 CONNECTOR HOUSING CS 638 3 1 COVER 2306 307A 1 COVER TOP 2520 324A 1 COVER BOTTOM 2520 326C 1 DISPLAY ASSEMBLY P 2400 110D 1 DISPLAY LENS 2520 311A 2 FOOT 428 319A 1 FOOT BLACK MOLDED POLY FE 12 4 FOOT BLACK MOLDED POLY FE 10 2 FOOT EXTRUDED FE 22A 2 FOOT RUBBER FE 6 1 FRONT PANEL MODIFIED 2520 305A 1 FUSE FU 106 1 6 1 FUSE HOLDER FH 39 1 HANDLE 428 329F 1 LED BLUE PL 112 3 1 LED HIGH POWER BLUE PL 118 1 1 LED RED GREEN PL 112 2 1 LENS LED 6517 309B 1 LINE CORD CO 7 1 MEMBRANE SWITCH FRONT PANEL 6430 313
87. R4 RES 100K 1 100MW THICK FILM R 418 100K R43 R49 RES 499 1 100MW THICK FILM R 418 499 R44 RES 2M 1 100MW THICK FILM R 418 2M R45 RES 39 2K 1 100MW THICK FILM R 418 39 2K R46 NTC THERMISTOR RT 24 R47 RES 1 74K 1 100MW THICK FILM R 418 1 74K R5 R23 RES 2 21K 1 100MW THIN FILM R 438 2 21K R50 RES 100 1 100MW THICK FILM R 418 100 R52 RES 100 1 100MW THICK FILM R 418 100 R60 RES IK 1 100MW THICK FILM R 418 1K R64 R66 RES 49 9 1 100MW THICK FILM R 418 49 9 R65 RES 10K 1 100MW THICK FILM R 418 10K R69 R70 RES 10M 1 125MW THICK FILM R 418 10M R71 RES 3 32K 1 100MW THICK FILM R 418 3 32K Model 2520 Pulsed Laser Diode Test System Service Manual Table 6 4 continued Pulse board parts list Replaceable Parts 6 15 Circuit designation Description Keithley part no R72 RES 332 1 100MW THICK FILM R 418 332 R76 RES 249 1 1W THIN FILM R 438 249 R77 R81 RES 100 1 100MW THIN FILM R 438 100 R8 RES 8 87K 1 1W THIN FILM R 438 8 87K R82 R83 R84 RES 2 21 1 100MW THICK FILM R 418 2 21 RTI THERMISTOR PD 7MW DEG C 1500V RT 8 613 74K TP8 TP10 CONN TESTPOINT CS 985 U1 U6 IC 12 BIT VOLTAGE OUTPUT DAC IC 1130 U10 U2 IC 8 STAGE SHIFT C074HC409AM IC 1026 U11 IC POS VOLTAGE REG 15V 500MA IC 194 78M15 U12 IC 5V VOLTAGE REGULATOR IC 576 LM2940CT U13 IC HCPL0631 PACK IC 1153 U14 U25 IC 5V VOLTAGE REGULATOR IC 184 U15 U19 IC VOLT C
88. RES 33 5 250mW METAL FILM R 376 33 Model 2520 Pulsed Laser Diode Test System Service Manual Replaceable Parts 6 7 Table 6 1 continued Mainframe digital board parts list Circuit designation Description Keithley part no R58 RES 20 1 100MW THICK FILM R 418 20 R62 RES 100 5 250MW METAL FILM R 376 100 R67 R87 RES 0499 1 100MW THICK FILM R 418 0499 R6 R11 R55 R63 R66 R69 R72 RES 1K 1 100MW THICK FILM R 418 1K R110 R74 R89 R92 R94 R103 R114 RES 10K 1 100MW THICK FILM R 418 10K R81 R86 R105 R106 R115 R116 RES 49 9 1 100MW THICK FILM R 418 49 9 R88 R93 R107 R108 R109 RES 10 10 100MW THICK FILM R 418 10 S037 503 504 SOCKET PLCC 032 T A SO 143 32 T1 TRANSFORMER TR 351A T2 TRANSFORMER TR 350A TP13 SURFACE MOUNT PCB TEST POINT CS 1026 Ul IC HIGH SPEED PWN CONTROLLER IC 1120 U13 IC SERIAL EPROM 24LC16B LSI 153 U15 IC MICROCONTROLLER MC68332 FC LSI 161 U16 IC 2 INPUT EXCLUSIVE OR GATE IC 1180 NC7SZ86 U19 IC OCTAL INTER BUS TRANS 75161 IC 647 U2 U17 IC 256K X 16 BIT CMOS RAM 17NS LSI 249 1 U20 IC 5V RS 232 TRANSCEIVER MAX202 IC 952 U21 U23 IC VOLTAGE REGULATOR LM317T IC 317 U22 U24 IC VOLTAGE REGULATOR LM337MP IC 309 U25 IC 5V VOLTAGE REGULATOR IC 576 LM2940CT U26 IC 5V LOW DROPOUT REGULATOR IC 1370 U27 U39 U40 LARGE SCALE IC SMT LSI 239 1 U28 U30 IC HEX SCHMITT INVERTER IC 1368 U29 U41 U42 IC 16 BIT BIDIRECTIONAL TRANSCEIV LSI 265 U3 PROGRAMMED ROM 2520 800B0
89. Voltage reading limits range voltage 1 year 18 C to 28 C 5V 5 0000V 4 9785 to 5 0215V 10V 10 000V 9 962 to 10 038V Figure 1 2 Connections for voltage measurement verification tests Calibrator 0 utput DC Voltage Model 2520 Testhead Output HI O OO ECO OO e Zoch BNC Cables 00000 VOLTAGE SENSEHI VOLTAGE O utput LO SEN SE LO 1 10 Performance Verification Model 2520 Pulsed Laser Diode Test System Service Manual Current source accuracy Follow the steps below to verify that Model 2520 current source accuracy is within speci fied limits This test involves setting the output current to a specific value and measuring the current with a digital multimeter 1 With the power off connect the digital multimeter and characterized 10Q to 15Q resistor to the testhead CURRENT OUTPUT jacks as shown in Figure 1 3 2 Turn on the Model 2520 and DMM and allow them to warm up for a minimum of one hour 3 Restore front panel BENCH defaults as outlined previously in Restoring factory defaults 4 Select the DC mode as follows a Press CONFIG then LASER I b Select SHAPE then press ENTER c Select DC then press ENTER d Press EXIT to return to normal display 5 Press the LASER Ij key then the EDIT key and select the Model 2520 500mA sour
90. age I V R Current measurement accuracy Follow the steps below to verify that Model 2520 detector current measurement accuracy is within specified limits This test involves applying currents and verifying that Model 2520 current readings are within required limits 1 With the power off connect the 2kO resistor and DMM to the testhead DETEC TOR 1 jack as shown in Figure 1 4 2 Turnon the Model 2520 and DMM and allow them to warm up for a minimum of one hour 3 Select the DMM DC volts function and enable auto range Figure 1 4 Connections for DETECTOR 1 current measurement verification tests Center Input HI Conductor Model 2001 DMM J M odel 2520 Testhead 00000000 TTO e Y D o ES RANGE D ED 4 cum e 6 VE A a amp E curo o Shield Resistor Input LO See Text DETECTOR 1 1 12 Performance Verification Model 2520 Pulsed Laser Diode Test System Service Manual 4 Restore front panel BENCH defaults as outlined previously in Restoring factory defaults 5 Press the DETECTOR I Ipp key then select the Model 2520 10mA range with the RANGE Y key 6 Press the DETECTOR 1 VB key then press the EDIT key and set the voltage bias source value to 20 000V 7 Turn on the Model 2520 outputs by pressing the ON OFF OUTPUT key 8 Press the TRIG key Note the DMM voltage reading then turn off the outputs by pressing the ON OFF OUTPUT key 9
91. al Calibration 2 9 Viewing calibration dates and calibration count When calibration is locked only the UNLOCK and VIEW DATES selections will be accessible in the calibration menu To view calibration dates and calibration count at any time 1 From normal display press MENU select CAL and then press ENTER The unit will display the following CALIBRATION UNLOCK EXECUTE VIEW D ATES p gt 2 Select VIEW DATES and then press ENTER The Model 2520 will display the next and last calibration dates and the calibration count as in the following example NEXT CAL 07 15 2002 Last cal 07 15 2001 Count 0001 Calibration errors The Model 2520 checks for errors after each calibration step minimizing the possibility that improper calibration may occur due to operator error Front panel error reporting If an error is detected during calibration the instrument will display an appropriate error message see Appendix B The unit will then prompt you to repeat the calibration step that caused the error Remote error reporting You can detect errors while in remote by testing the state of EAV Error Available bit bit 2 in the status byte Use the STB query to request the status byte Query the instrument for the type of error by using the SYST ERR query The Model 2520 will respond with the error number and a text message describing the nature of the error See Appendix B for details Aborting calibration steps To abort a calib
92. alues 2 Repeat steps for both fast and slow pulse transition See procedure 3 Calculate current from voltage measurement and actual resistance I V R 2 28 Calibration Model 2520 Pulsed Laser Diode Test System Service Manual 16 Repeat steps 5 through 14 to calibrate the slow transition pulse 17 Repeat steps 3 through 16 for the 5A range with the following exceptions Use the 1 2 to 1 6Q resistor e Select the 5A source range with this command SOUR1 CURR RANG 5 e Set the appropriate 10 0 5 and 90 4 5 of range values using this command SOURI CURR Current 18 Send this command to turn off the output OUTP1 OFF Step 4 Pulse low calibration Follow these steps to calibrate current source pulse low Table 2 11 summarizes calibra tion resistances and commands 1 Connect the 100Q resistor and DMM to the Model 2520 testhead CURRENT OUTPUT jacks as shown in Figure 2 4 Select the DMM DC volts function and enable auto range 3 Put the unit into the pulse mode SOUR1 FUNC SHAP PULS 4 Send this command to turn on the source output OUTP1 ON 5 Enable fast transition pulses SOUR1 PULS TRAN STAT OFF 6 Send the following command to select the 500mA current range SOUR1 CURR RANG 0 5 7 Send this command to set the current to 15mA SOUR1 CURR LOW 15e 3 8 Note the DMM reading then calculate the current from the voltage and actual resistance adding a slight offset value I V R 90uA 9 Send th
93. and to output 20V SOU R2 VOLT 20 Note and record the DMM reading and then send the negative of that value as the parameter for the following command CAL PRO T SO UR2 lt DMM Reading Send this command to turn off the outputs OUTP1 OFF Disconnect VOLTAGE SENSE HI from ground DIAG KEIT FCON HI OFF Repeat steps 3 through 12 for detector 2 using Table 2 12 as a guide Be sure to Connect the DMM to the testhead DETECTOR 2 and VOLTAGE SENSE HI jacks Figure 2 6 Send source values using the SOUR3 VOLT command where appropriate Calibrate each point using the CAL PROT SOUR3 command Model 2520 Pulsed Laser Diode Test System Service Manual Calibration 2 31 Table 2 12 Remote voltage bias source calibration summary Voltage bias channel Calibration voltages Calibration commands Detector 1 DIAG KEIT FCON HI ON OUTP1 ON 20V SOUR2 VOLT 20 CAL PROT SOUR2 lt DMM Reading OV SOUR2 VOLT 0 CAL PROT SOUR2 lt DMM_Reading gt 20V SOUR2 VOLT 20 CAL PROT SOUR2 lt DMM_Reading gt OUTP1 OFF DIAG KEIT FCON HI OFF Detector 2 DIAG KEIT FCON HI ON OUTP1 ON 20V SOUR3 VOLT 20 CAL PROT SOUR3 lt DMM Reading OV SOUR3 VOLT 0 CAL PROT SOUR3 lt DMM_Reading gt 20V SOUR3 VOLT 20 CAL PROT SOUR3 lt DMM_Reading gt OUTP1 OFF DIAG KEIT FCON HI OFF Command parameter values are negative of the displayed DMM reading Step 6 Current measuremen
94. ay the following message DMM RDG 00 00000 V Use lt P A V ENTER or EXIT 11 Note the DMM voltage reading then use the EDIT keys to adjust the Model 2520 display value to agree with the reading 12 Press ENTER The unit will display the prompt for the 20V calibration point Vbias 1 CAL Press ENTER to Output 420 000 V 13 Press ENTER The instrument will display the following message DMM RDG 20 00000 V Use lt P A Y ENTER or EXIT 14 Note the DMM voltage reading then use the EDIT keys to adjust the Model 2520 display value to agree with the reading and press ENTER 15 Press EXIT to return to normal display 16 Repeat steps 4 through 15 for the DETECTOR 2 bias voltage source Make your connections to the testhead DETECTOR 2 jack Figure 2 6 and select Vb2 for calibration Figure 2 6 Detector 2 voltage bias source calibration connections Input HI Model 2001 DMM A M odel 2520 Testhead m e Triax Cable Inner Shield o 00000 cm O ums Eee POWER o4 gt e OO LD CL DETECTOR 1 DETECTOR2 VOLTAGE SEN SE HI 2 18 Calibration Model 2520 Pulsed Laser Diode Test System Service Manual Step 6 Current measurement calibration Follow the steps below to calibrate all photodiode current measurement ranges Table 2 7 summarizes calibration ranges and resistors Table 2 7 Current measurement calibration values Current range Calibra
95. bling you to perform the calibration procedures cal prot code lt password gt Up to an 8 character string including letters and numbers The CODE command sends the password code and enables calibration when performing these procedures via remote The correct password must be sent to the unit before sending any other calibration command The default remote password is KI002520 The CODE command should be sent only once before performing calibration Do not send CODE before each calibration step To change the code first send the present code then send the new code The password parameter must be enclosed in single quotes If you change the first two characters of the password to something other than KI you will not be able to unlock calibration from the front panel CAL PROT CODE KI002520 Send default code of KI002520 CALibration PRO Tected CO UNT Purpose Format Response Description Example To request the number of times the Model 2520 has been calibrated cal prot count Number of times calibrated The COUNT query may be used to determine the total number of times the Model 2520 has been calibrated CAL PROT COUNT Request calibration count B 4 Calibration Reference LOCK Model 2520 Pulsed Laser Diode Test System Service Manual C ALibration PRO Tected LO CK Purpose Format Query Response Description Note Example SAVE To lock out calibration cal p
96. bration 2 11 Step 1 Prepare the Model 2520 for calibration 1 5 Turn on the Model 2520 and the calibration equipment and allow them to warm up for a minimum of one hour before performing calibration Press the MENU key choose CAL and press ENTER Select UNLOCK and then press ENTER The instrument will display the following PASSWORD Use 4 gt gt A Y ENTER or EXIT Use the EDIT A and Y keys to select the letter or number and use the lt and gt arrow keys to choose the position Press EDIT A for letters W for numbers Enter the present password on the display Front panel default 002520 Press ENTER to complete the process Press EXIT to return to normal display Step 2 Voltage measurement calibration Follow the steps below to calibrate both voltage measurement ranges Table 2 4 summa rizes calibration ranges and voltages 1 From normal display press the Model 2520 LASER Vj key then select the 10V range using the RANGE A key 2 Press the MENU key select CAL then press ENTER 3 Select EXECUTE then press ENTER to enter the CAL EXECUTION menu 4 Select VL then press ENTER The unit displays the following VL CAL Remove all inputs 5 Make sure all signal cables are disconnected from the testhead then press ENTER The instrument will display VL CAL Connect Calibrator HI to V sense p gt LO and set it to 10 000V Table 2 4 Voltage measurement calibration values Voltage range Calibratio
97. cables or jumpers installing or removing switching cards or making internal changes such as installing or removing jumpers Do not touch any object that could provide a current path to the common side of the circuit under test or power line earth ground Always make measurements with dry hands while standing on a dry insulated surface ca pable of withstanding the voltage being measured The instrument and accessories must be used in accordance with its specifications and operating instructions or the safety of the equipment may be impaired Do not exceed the maximum signal levels of the instruments and accessories as defined in the specifications and operating information and as shown on the instrument or test fixture panels or switching card When fuses are used in a product replace with same type and rating for continued protection against fire hazard Chassis connections must only be used as shield connections for measuring circuits NOT as safety earth ground connections If you are using a test fixture keep the lid closed while power is applied to the device under test Safe operation requires the use of a lid interlock Ifa E screw is present connect it to safety earth ground using the wire recommended in the user documentation The IN symbol on an instrument indicates that the user should refer to the operating instructions located in the manual The A symbol on an instrument shows that it can source or measure 1000 volt
98. cations You can use alternate equipment as long as that equipment has specifications at least as good as those listed in Table 1 1 Keep in mind however that test equipment uncertainty will add to the uncertainty of each measurement Generally test equipment uncertainty should be at least four times better than corresponding Model 2520 specifications Table 1 1 Recommended verification equipment Description Manufacturer Model Specifications Calibrator Fluke 5700A DC Voltage 5V 5ppm 10V 5ppm Digital Keithley 2001 DC Voltage 20V 22ppm Multimeter Resistance 200 59ppm 200Q 43ppm 2KQ 37ppm Precision 1 2 to 1 6Q 5W 5 er sk rad 4 coefficient Resistors epe 25 20ppm C for i VO all resistors 4000 1W 1 1kQ 0 5W 1 2kQ 0 25W 1 90 day accuracy specifications of lowest usable range for specified output 90 day full range accuracy specifications Characterize resistors to within 100ppm using 4 wire ohms function of digital multimeter before use Use only non inductive metal film or bulk metal resistors UN ma Resistor characterization The precision resistors listed in Table 1 1 should be characterized to within 100ppm using the 4 wire ohms function of the digital multimeter before use Use the characterized values when performing the verification procedure 1 6 Performance Verification Model 2520 Pulsed Laser Diode Test System Service Manual The verification limits l
99. ce range with the RANGE Y key 6 Select the DMM DC voltage function and enable auto range 7 Press the EDIT key to enter the EDIT mode Using the EDIT A and WV or numeric keys set the Model 2520 current source output to 500 00mA then turn on the out puts by pressing the ON OFF OUTPUT key 8 Note the DMM voltage reading then turn off the output by pressing the ON OFF OUTPUT key Figure 1 3 Connections for current source verification tests Model 2001 DMM Input HI Model 2520 Testhead DETECTOR 1 DETECTOR POWER 10 to 15Q Resistor Input LO 500mA R CURRENT CURRENT i to 160 uos OUTPUTHI OUTPUTLO 5A Range Model 2520 Pulsed Laser Diode Test System Service Manual Performance Verification 1 11 9 Calculate the current using the voltage value and characterized resistance value I V R Recalculate reading limits from these values then verify that the current is within those limits 10 Replace the 10Q to 15Q resistor with the characterized 1 20 to 1 60 resistor 11 Repeat steps 5 through 9 for the 5A range using the 1A value shown in Table 1 3 Table 1 3 Current source verification limits Model 2520 Output current limits range Test resistance Output current 1 year 18 C to 28 C 500mA 10 to 15Q 500 000mA 498 55mA to 501 45mA 5A 1 2 to 1 60 1 0000A 0 9935 to 1 0065A Nominal values Recalculate limits from characterized resistance and measured volt
100. d CAL PRO T S0 UR1 PROT Voltage 10 Send this command to turn off the output OUTP1 OFF Table 2 14 Remote compliance calibration summary Command Description SOUR1 FUNC SHAP DC Select DC source mode OUTP1 ON Turn output on SOUR1 CURR 0 1 Source 100mA SOURI VOLT PROT 10 5 Set compliance to 10 5V CAL PROT SOUR1 PROT DMM Reading Calibrate 10 5V compliance SOURI VOLT PROT 3 Set compliance to 3V CAL PROT SOUR1 PROT DMM Reading Calibrate 3V compliance OUTP1 OFF Turn output off Model 2520 Pulsed Laser Diode Test System Service Manual Calibration 2 37 Step 8 Program calibration dates Use the following commands to set the calibration date and calibration due date CAL PROT DATE lt yyyy gt lt mm gt lt dd gt Calibration date CAL PROT NDUE lt yyyy gt mm lt dd gt N ext calibration due date Note that the year month and date must be separated by commas Step 9 Save calibration constants Calibration is now complete You can store the calibration constants in EEROM by send ing the following command CAL PRO T SAVE NOTE Calibration will be temporary unless you send the SAVE command Step 10 Lock out calibration To lock out further calibration send the following command after completing the calibra tion procedure CAL PRO T LO CK Routine M aintenance 3 2 Routine Maintenance Model 2520 Pulsed Laser Diode Test System Service Manual Introduction The information
101. dicates that the front panel display processor has stopped communicating with the main processor which is located on the motherboard This error indicates that the main processor ROMs U3 and U4 may require re seating in their sock ets The ROMs may be reseated as follows 1 Turn off the power and disconnect the line cord and all other test leads and cables from the instrument Remove the case cover as outlined in Section 5 3 Locate the firmware ROMs U3 and U4 located on the motherboard These ROMs are the only IC installed in a socket Refer to the component layout drawing at the end of Section 6 for exact location 4 Carefully push down on the ROM ICs to make sure it is properly seated in its socket CAUTION Be careful not to push down excessively The motherboard could crack 5 Connect the line cord and turn on the power If the problem persists additional troubleshooting will be required D isassembly 5 2 Disassembly M odel 2520 Pulsed Laser Diode Test System Service Manual Introduction This section explains how to handle clean and disassemble the Model 2520 Pulsed Laser Diode Test System Disassembly drawings are located at the end of this section Handling and cleaning To avoid contaminating PC board traces with body oil or other foreign matter avoid touching the PC board traces while you are repairing the instrument Certain board areas have high impedance devices or sensitive circuitry where contamination
102. e 1 A Rw a 10 11 12 Figure 2 9 Connect the DMM to the CURRENT OUTPUT jacks as shown in Figure 2 9 Select the DC volts function and enable auto range From normal display press LASER Ij then press the EDIT key Press the EDIT p key Select the 500mA key with the RANGE y key Using the EDIT lt and p keys and EDIT A and W keys set the current source to 100 00mA Press the MENU key select CAL then press ENTER Select EXECUTE then press ENTER to enter the CAL EXECUTION menu Select COMPLIANCE then press ENTER The unit displays the following Compliance CAL Press ENTER to Output 10 500V Press ENTER The instrument will display DMM RDG 10 500 V Use 4 gt A V ENTER or EXIT Note the DMM reading then adjust the Model 2520 display to agree with that value Press ENTER The instrument will display DMM RDG 03 000 V Use gt A Y ENTER or EXIT Note the DMM reading then adjust the Model 2520 display to agree with that value Press ENTER to complete compliance calibration Compliance calibration connections Model 2001 DMM Model 2520 Testhead Input HI DETECTOR 1 DETECTOR 2 KEITHLEY DL ror y S 2001 MULTIMETER Lo T L A CE i 1 i CURRENT CURRENT OUTPUT HI OUTPUT LO Model 2520 Pulsed Laser Diode Test System Service Manual Calibration 2 21 Step 8 Enter calibration dates and save calibration NOTE For temporary cal
103. e bar separates from the casing Pull the display board from the front panel Remove the switch pad by pulling it from the front panel 5 6 Disassembly M odel 2520 Pulsed Laser Diode Test System Service Manual Removing power components The following procedures to remove the power supply and or power module require that the case cover and motherboard be removed as previously explained Power supply module removal Perform the following steps to remove the power supply module 1 Disconnect the wires that connect the power supply module on the bottom of the chassis to the rear panel power module 2 Remove the screws that secure the power supply to the chassis bottom then remove the module Power module removal Perform the following steps to remove the rear panel power module 1 Disconnect the power module s ground wire This green and yellow wire connects to a threaded stud on the chassis with a kep nut 2 Squeeze the latches on either side of the power module while pushing the module from the access hole Instrument re assembly Re assemble the instrument by reversing the previous disassembly procedures Make sure that all parts are properly seated and secured and that all connections are properly made WARNING To ensure continued protection against electrical shock verify that power line ground green and yellow wire attached to the power mod ule is connected to the chassis Also make sure the ground wires are attac
104. e calculated current value as the parameter for the following command CAL PROT SOUR1 LOW Calculated current For example if the current is 14 5mA the correct command is CAL PRO T SO URL LOW 14 59e 3 10 Send this command to set the current to 1 5mA SSOU RI CURR LOW 1 5e 3 11 Note the DMM reading then calculate the current from the voltage and actual resistance subtracting a slight offset value I V R 75uA 12 Send the calculated current value as the parameter for the following command CAL PROT SOUR1 LOW Calculated current Model 2520 Pulsed Laser Diode Test System Service Manual Calibration 2 29 13 Enable slow pulses SOU R1 PULS TRAN STAT ON 14 Repeat steps 5 through 12 15 Send this command to turn off the output OUTP1 OFF 16 Disconnect the 100Q resistor then connect the 10Q resistor in its place 17 Repeat steps 3 through 15 for the 5A range with the following changes Select the 5A range SOUR1 CURR RANG 5 Use these commands to set the two low current values SOUR1 CURR LOW 0 15 SOUR1 CURR LOW 0 015 e Use 900uA and 750uA respectively as the offsets when calculating the CAL PROT SOUR1 LOW parameter Table 2 11 Remote pulse low calibration summary Current range Calibration resistance Calibration commands N A SOUR 1 FUNC SHAP PULS OUTP1 ON 500mA 1000 SOUR 1 PULS TRAN STAT OFF ON SOUR 1 CURR RANG 0 5 SOURI CURR LOW 15e 3 CAL PROT SOUR1 LOW Current 90 A gt SOURI
105. en 1 11 Voltage bias source accuracy rrrnrrvvvrvrnvvrenrevvrevrevrarvravrarerernsee 1 13 Calibration Huic 2 2 Environmental conditions sese 2 4 Temperature and relative humidity 2 4 Warm up Perdis ince iiio pie te iii 2 4 Line POW EL snakke 2 4 Calibration considerations essere 2 4 Calibration Cycle aeterne in 2 5 Recommended calibration equipment 2 5 Resistor characterization rrnrnrnnrvrnvravvravvrvvrvrnrnvvernvevveneee 2 5 Calibration menus cintia 2 6 Unlocking calibration ernorrnrnnvrrnvnvnrvnrnrvevrrnvrevvrnvravvsreraverervsenr 2 7 Unlocking calibration from the front panel 2 7 Unlocking calibration by remote sees 2 7 Changing the password essere 2 8 Changing the password from the front panel 2 8 Changing the password by remote sesessss 2 8 Resetting the calibration password sees 2 8 Viewing calibration dates and calibration count 2 9 Calibration ere i I eerie lc 2 9 Front panel error reporting ssesesseeeee 2 9 Remote error reporting sss 2 9 Aborting calibration steps esnrrnvnrvnrnrnvnervrnvravvrnvnrverernsvrsesnsenvere 2 9 Testhead CONNECTIONS eri eire reir diari de der 2 10 Front panel calibration
106. hed to the power transformer mounting screws Also ensure the six bottom case screws are properly installed to secure and ground the case cover to the chassis Model 2520 Pulsed Laser Diode Test System Service Manual Disassembly 5 7 Testhead disassembly Follow the procedures below in the following order to disassemble the testhead Case disassembly 1 Remove the eight screws that secure the case top to the case bottom 2 Remove the nuts and washers that secure the four BNC PULSED and two triax DETECTOR jacks to the front panel 3 Slide the case top forward until it clears the BNC and triax jacks then continue sliding the case top forward away from the case bottom Output board removal 1 Remove the two screws that secure the REMOTE INTERLOCK connector to the rear panel Remove the nut that secures the KEY INTERLOCK to the rear panel Unplug the ribbon cable from J4 Remove the three screws that secure the output board to the standoffs Pull the output board forward until the KEY INTERLOCK and REMOTE INTER LOCK connector clear the rear panel then remove the output board SAC obe ua ia Input board removal 1 Remove the two screws that secure the MAINFRAME CONN 1 connector to the front panel 2 Unplug the MAINFRAME CONN 2 ribbon cables from the input board 3 Unplugthe INTERLOCK STATUS and POWER ON indicator light cables from J5 and J6 Remove the screws and standoffs that secure the input board to the case bot
107. here I current setting D duty cycle K 0 5 for time 5 minutes 1 for time gt 5 minutes This derating must also be applied for a period equal to the time that yD I was gt 0 2 Not including overshoot and settling time Pulse mode only Output 500mA DC on 500mA range and 1A DC on 5A range 5 See Figure 4 for test configuration 7 Figures 1 and 2 are typical pulse outputs into resistive loads 3 Typical Per ANSI IEEE Std 181 1977 10 Per ANSI IEEE Std 181 1977 10 to 90 1 DC accuracy 700mV output terminal 0 20 typical output impedance 12 At DC 10us measurement pulse width Filter off 13 Standard deviation of 10 000 readings with 10us pulse width filter off with I source set to 0 amps DC 4 The A D converter has 14 bit resolution The useful resolution is improved by reading averaging The useful resolution is Range 1 255 Pulse Width ns 400ns 100ns w gt a Useful Resolution Averaging Filter Setting 5 Excluding total programmed Pulse ON time Pulse OFF time 5 Front panel off calc off filter off duty cycle 10 binary communications Returning 1 voltage and 2 current measurements for each source point 8 Sweep mode Specifications are subject to change without notice Specifications A 5 Pulse Waveform Flatness 500mA Into 20 Ohms Pulse Output Trigger Output Relationship 0 6 T 0 515 i Full Pulse Trigger 0 5 Tex a gt i gt ate
108. ibration without saving new calibration constants proceed to Step 9 Lock out calibration 1 From the CALIBRATION menu select SAVE and then press ENTER The unit will prompt you for the calibration date CAL DATE 08 15 2001 Use lt gt A V ENTER or EXIT 2 Using the EDIT keys change the displayed date to today s date and then press the ENTER key Press ENTER again to confirm the date 3 The unit will then prompt for the calibration due date NEXT CAL 08 15 2002 Use lt gt A V ENTER or EXIT 4 Setthe calibration due date to the desired value and then press ENTER Press ENTER again to confirm the date 5 Once the calibration dates are entered calibration is complete and the following message will be displayed CALIBRATION COMPLETE Press ENTER to save EXIT to abort 6 Press ENTER to save the calibration data or press EXIT to abort without saving calibration data Step 9 Lock out calibration From the CAL EXECUTION menu select LOCK and then press ENTER to lock out cal ibration Press EXIT to return to normal display 2 22 Calibration Remote calibration Model 2520 Pulsed Laser Diode Test System Service Manual Use the following procedure to perform remote calibration by sending SCPI commands over the IEEE 488 bus or RS 232 port The remote commands and appropriate parameters are separately summarized for each step Remote calibration command summary Table 2 8 summarizes only those remote calibrat
109. ing verification tests NOTE Both interlocks must be enabled to perform the verification tests Figure 1 1 Testhead connections Model 2520 Mainframe Model 2520 Testhead WARNING wo INTERNAL OPERATOR SERVICABLE PARTS SERVICE BY QUALIFIED PERSONNEL ONLY DISABLED rn CONN 2 Cable CONN 1 Cable Model 2520 Pulsed Laser Diode Test System Service Manual Performance Verification 1 9 Voltage measurement accuracy Follow the steps below to verify that Model 2520 laser diode voltage measurement accu racy is within specified limits This test involves applying accurate voltages from a DC calibrator and verifying that the Model 2520 voltage readings are within specified limits 1 With the power off connect the voltage calibrator to the testhead VOLTAGE SENSE jacks as shown in Figure 1 2 2 Turn on the Model 2520 and calibrator and allow them to warm up for a minimum of one hour 3 Restore BENCH defaults as covered previously in Restoring factory defaults Press the LASER Vj key then select the Model 2520 5V range with the RANGE W key 5 Set the calibrator source voltage to 5 0000V and turn on the output 6 Press the TRIG key then verify the Model 2520 voltage reading is within the limits for the 5V range shown in Table 1 2 7 Repeat steps 4 through 6 for the 10V range with a 10V input voltage as covered in Table 1 2 Table 1 2 Voltage measurement accuracy limits Model 2520 Calibrator
110. ion B 10 Generating an SRQ on calibration complete B 11 Using the OPC command B 11 Using the OPC query B 10 Disassembly 5 1 Environmental conditions 2 4 Line power 2 4 Temperature and relative humidity 2 4 Warm up period 2 4 Factory service 6 2 Front panel calibration 2 10 Front panel disassembly 5 5 Front panel tests 4 3 CHAR SET test 4 4 DISPLAY PATTERNS test 4 3 KEYS test 4 3 Handling and cleaning 5 2 Handling PC boards 5 2 Solder repairs 5 2 Instrument re assembly 5 6 Line fuse replacement 3 2 Measurement commands B 6 DATA B 6 SENSe B 6 Miscellaneous commands B 3 CODE B 3 COUNT B 3 DATE B 5 LOCK B 4 NDUE B 5 SAVE BA Model 2520 rear panel 3 2 Motherboard removal 5 4 No comm link error 4 16 Ordering information 6 2 Parts lists 6 2 Mainframe digital board 6 3 Mainframe display board 6 9 Miscellaneous 6 16 Pulse board 6 13 Test head board 6 10 Performance Verification 1 1 Performing the verification test procedures 1 7 Test considerations 1 7 Test summary 1 7 Power line fuse 3 3 Power on self test 4 2 Principles of operation 4 4 Analog circuits 4 6 A D converters 4 6 Measurement circuits 4 6 Source circuits 4 8 Digital circuitry 4 10 Digital signal processor 4 10 Display board circuits 4 10 TO circuits 4 10 Microcontroller 4 10 Overall block diagram 4 4 Power supply 4 9 Recommended test equipment 1 5 Resistor characterization 1 5 Remote calibration 2 22 command summary 2 22
111. ion commands used in this section NOTE Fora detailed description of all calibration commands and queries refer to Appendix B Table 2 8 Remote calibration command summary Command Description CALibration Calibration subsystem PROTected Calibration commands protected by password CODE lt password gt Unlock calibration Default password KI002520 CODE Query password if calibration is unlocked SENSe 1 lt NRf gt Calibrate active range of voltage measurement SENSe2 lt NRf gt Calibrate active range of detector I current measurement SENSe3 lt NRf gt Calibrate active range of detector 2 current measurement SOURce 1 lt NRf gt Calibrate active range of current source PROTection lt NRf gt Calibrate voltage compliance LOW lt NRf gt Calibrate current source pulse low output level SOURce2 lt NRf gt Calibrate detector 1 voltage bias source SOURce3 lt NRf gt Calibrate detector 2 voltage bias source DATE lt yyyy gt lt mm gt lt dd gt Program calibration year month day NDUE lt yyyy gt lt mm gt lt dd gt Program calibration due year month day SAVE Save calibration constants in EEPROM LOCK Lock out calibration DIAGnostic Diagnostic subsystem KEIThley FCON HI lt b gt Internally connect VOLTAGE SENSE HI input to floating ground LO lt b gt Internally connect VOLTAGE SENSE LO input to floating ground Model 2520 Pulsed Laser Diode Test System Service Manual Ca
112. isted in this section have been calculated using only the Model 2520 one year accuracy specifications they do not include test equipment uncertainty If a particular measurement falls outside the allowable range recalculate new limits based on Model 2520 specifications and corresponding test equipment specifications Example limits calculation As an example of how verification limits are calculated assume you are testing the 10mA measurement range with a 10mA input current Using the Model 2520 one year accuracy specification of 0 3 of reading 20uA offset the calculated reading limits are Limits 10mA 10mA x 0 3 204A Limits 10mA 30HA 20uA Limits 10mA 50uA Limits 9 95mA to 10 05mA Restoring factory defaults Before performing the verification procedures restore the instrument to its factory front panel BENCH defaults as follows 1 Press the SETUP key The instrument will display the following prompt SAVESETU P MENU SAVE RESTORE POWERON RESET 2 Select RESET then press ENTER The unit displays RESET ORIGINAL DFLTS BENCH GPIB 3 Select BENCH then press ENTER to restore BENCH defaults Model 2520 Pulsed Laser Diode Test System Service Manual Performance Verification 1 7 Performing the verification test procedures Test summary Detector current measurement accuracy Laser diode voltage measurement accuracy Laser diode current source accuracy Detector voltage bias source accu
113. ital board parts list Circuit designation Description Keithley part no C10 CAP 33UF 20 50V CERAMIC C 237 33 C105 C106 C146 C147 C186 C187 CAP 22P 5 100V CERAMIC C 465 22P C108 CAP 1UF 20 35V TANTALUM C 494 1 C111 CAP 1UF 20 100V CERAMIC C 436 1 C116 CAP 10U 20 16V TANTALUM C 546 10 C128 C132 C136 C137 C1 CAP 22U 20 25V ALUM ELEC C 609 22 C17 C22 C28 C30 C13 C15 C83 C85 CAP 220PF 10 100V CERAMIC C 451 220P C133 C135 C60 C63 C65 C67 CAP 1UF 20 50V CERAMIC C 418 1 C72 C76 C82 C14 CAP 2200P 1 50V CERAMIC C 532 2200P C140 C141 C169 C171 C178 C179 CAP 22U 20 25V ALUM ELEC C 609 22 C182 C183 C142 C145 C159 C166 C168 CAP 1UF 20 50V CERAMIC C 418 1 C173 C177 C184 C148 C153 CAP 1000P 10 100V CERAMIC C 451 1000P C158 CAP 100U 20 16V ALUM ELEC C 547 100 C16 C46 C49 C101 C102 C104 CAP 100PF 5 100V CERAMIC C 465 100P C138 C139 C172 CAP 33PF 5 100V CERAMIC C 465 33P C180 C181 CAP 100PF 5 100V CERAMIC C 465 100P C185 C103 C107 C110 C112 C113 CAP 1UF 20 50V CERAMIC C 418 1 C120 C127 C189 CAP 01uF 20 50V CERAMIC C 418 01 C190 C87 C93 C96 C100 C109 CAP 22U 20 25V ALUM ELEC C 609 22 C117 C119 C19 C21 C42 C45 C154 C160 CAP 01uF 20 50V CERAMIC C 418 01 C163 C165 C188 C202 C205 C207 C210 C214 CAP 1UF 20 50V CERAMIC C 418 1 C206 C208 C309 C310 C311 CAP 01uF 20 50V CERAMIC C 418 01 C216 C217 C219 C220 C22
114. lets you check the functionality of each front panel key Perform the fol lowing steps to run the KEYS test 1 Display the MAIN MENU by pressing the MENU key 2 Using the EDIT keys select TEST and press ENTER to display the SELF TEST MENU 3 Select DISPLAY TESTS and press ENTER to display the following menu FRONT PANEL TESTS KEYS DISPLAY PATTERNS CHAR SET 4 Select KEYS and press ENTER to start the test When a key is pressed the label name for that key will be displayed to indicate that it is functioning properly When the key is released the message No keys pressed is displayed 5 Pressing EXIT tests the EXIT key However the second consecutive press of EXIT aborts the test and returns the instrument to the SELF TEST MENU Continue pressing EXIT to back out of the menu structure DISPLAY PATTERN S test The display test lets you verify that each pixel and annunciator in the vacuum fluorescent display is working properly Perform the following steps to run the display test 1 Display the MAIN MENU by pressing the MENU key 2 Select TEST and press ENTER to display the SELF TEST MENU 3 Select DISPLAY TESTS and press ENTER to display the following menu FRONT PANEL TESTS KEYS DISPLAY PATTERNS CHAR SET 4 Select DISPLAY PATTERNS and press ENTER to start the display test There are five parts to the display test Each time a front panel key except EXIT is pressed the next part of the test sequence is selected
115. libration 2 23 Remote calibration procedure Step 1 Prepare the Model 2520 for calibration 1 With the power off connect the Model 2520 to the controller IEEE 488 interface or RS 232 port using a shielded interface cable 2 Turn on the Model 2520 and the test equipment and allow them to warm up for a minimum of one hour before performing calibration 3 If you are using the IEEE 488 interface make sure the primary address of the Model 2520 is the same as the address specified in the program you will be using to send commands Use the COMM key to access the IEEE 488 address 4 Send the following command to unlock calibration CAL PROT CO DE K1002520 2 24 Calibration Model 2520 Pulsed Laser Diode Test System Service Manual Step 2 Voltage measurement calibration Follow these steps to calibrate voltage measurements Table 2 9 summarizes calibration voltages and commands 1 10 Put the unit into the DC mode with this command SOU R1 FUNC SHAP DC Send the following command to select the 10V range SEN S1 VOLT RANG 10 Disconnect all signal cables from the testhead Send the following commands in order DIAG KEIT FCON HION DIAG KEIT FCON LO ON SEN S1 VOLT POL NEG CAL PRO T SEN S1 0 SEN S1 VOLT POL POS CAL PRO T SEN S1 0 DIAG KEIT FCON LO OFF Connect the calibrator to the Model 2520 testhead VOLTAGE SENSE jacks as shown in Figure 2 2 Set the calibrator voltage output to 10 000V and turn
116. libration Reference B 7 Current source commands SO U Rce 1 CALibration PRO Tected SO U Rce 1 Purpose To calibrate the current source Format cal prot sourl Resistance Parameters Resistance 10 to 15Q 500mA range 1 2 to 1 6Q 5A range Description The CAL PROT SOUR1 command calibrates the current source Dur ing the calibration process this command is sent with the appropriate resistance connected to the testhead see Section 2 Example CAL PROT SOUR1 10 Calibrate 500mA range DATA CALibration PRO Tected SO U Rce 1 D ATA Purpose To query current source calibration constants Query cal prot sourl data Description The CAL PROT SOUR1 DATA query requests current source calibra tion constants Returned constants are in ASCII format separated by commas Example CAL PROT SOUR1 DATA Query current source constants PRO Tection CALibration PRO Tected SO U Rce 1 PRO Tection CALibration PRO Tected SO U Rce 1 PRO Tection D ATA Purpose To calibrate the voltage compliance DAC Format cal prot sourl prot Query cal prot sourl prot data Description The CAL PROT SOUR1 PROT command calibrates the current source voltage compliance DAC The CAL PROT SOUR1 PROT DATA query requests voltage compliance DAC calibration constants Returned constants are in ASCII format separated by commas Example CAL PROT SOUR1 PROT Calibrate voltage compliance DAC B 8 Calibration Reference
117. lly designed to prevent static build up Typically you will receive these parts in anti static containers made of plastic or foam Keep these devices in their original containers until ready for installation Remove the devices from their protective containers only at a properly grounded work station Also ground yourself with a suitable wrist strap Handle the devices only by the body do not touch the pins e Ground any printed circuit board into which a semiconductor device is to be inserted to the bench or table e Use only anti static type desoldering tools e Use only grounded tip solder irons Once the device is installed in the PC board it is normally adequately protected and you can handle the boards normally Assembly drawings Use the assembly drawings located at the end of this section to assist you as you disassem ble and re assemble the Model 2520 Also refer to these drawings for information about the Keithley part numbers of most mechanical parts in the unit 5 4 Disassembly M odel 2520 Pulsed Laser Diode Test System Service Manual Case cover removal Follow the steps below to remove the case cover to gain access to internal parts WARNING Before removing the case cover disconnect the line cord and any test leads from the instrument 1 Remove handle The handle serves as an adjustable tilt bail Adjust its position by gently pulling it away from the sides of the instrument case and swinging it up
118. manual The procedures explicitly state if the operator may perform them Otherwise they should be performed only by service personnel Service personnel are trained to work on live circuits and perform safe installations and repairs of prod ucts Only properly trained service personnel may perform installation and service procedures Keithley products are designed for use with electrical signals that are rated Installation Category I and Installation Category II as described in the International Electrotechnical Commission IEC Standard IEC 60664 Most measurement control and data I O signals are Installation Category I and must not be directly connected to mains voltage or to voltage sources with high transient over voltages Installa tion Category II connections require protection for high transient over voltages often associated with lo cal AC mains connections The user should assume all measurement control and data I O connections are for connection to Category I sources unless otherwise marked or described in the Manual Exercise extreme caution when a shock hazard is present Lethal voltage may be present on cable con nector jacks or test fixtures The American National Standards Institute ANSI states that a shock haz ard exists when voltage levels greater than 30V RMS 42 4V peak or 60VDC are present A good safety practice is to expect that hazardous voltage is present in any unknown circuit before measuring Users of this prod
119. ment will prompt for OV calibration Ipd 1 CAL Press ENTER to Output 00 000 V 11 Press ENTER The unit will display DMM RDG 00 000 V Use lt gt A V ENTER or EXIT 12 Use the EDIT keys to adjust the Model 2520 display value to agree with the DMM reading 13 Press ENTER The instrument will prompt for calibration with 20V Ipd 1 CAL Press ENTER to Output 20 000 V 14 Press ENTER The unit will display DMM RDG 20 000 V Use d gt A V ENTER or EXIT 15 Use the EDIT keys to adjust the Model 2520 display value to agree with the DMM reading then press ENTER 16 Press EXIT to return to normal display 17 Repeat steps 3 through 16 for the 20mA 50mA and 100mA ranges using Table 2 7 as a guide Be sure to set the Model 2520 to the correct range using the RANGE A and Y keys and use the correct resistor for each range 18 Repeat steps 3 through 17 for the DETECTOR 2 measurement channel Make cali brator connections to the testhead DETECTOR 2 jack see Figure 2 8 Figure 2 8 Detector 2 current measurement calibration connections Conductor Model 2001 DMM M CECI Model 2520 Testhead 200000000 Inner e Q aD an E GD Qoa 0 petecton peTECTOr ceu EE Shield Resistor Put See Text Input LO DETECTOR 2 2 20 Calibration Model 2520 Pulsed Laser Diode Test System Service Manual Step 7 Compliance calibration Follow the steps below to calibrate complianc
120. n procedures at an ambient temperature of 18 28 C 65 82 F with relative humidity of less than 70 unless otherwise noted Warm up period Allow the Model 2520 to warm up for a minimum of one hour before performing calibration If the instrument has been subjected to temperature extremes those outside the ranges stated above allow additional time for the instrument s internal temperature to stabilize Typically allow one extra hour to stabilize a unit that is 10 C 18 F outside the specified temperature range Also allow the test equipment to warm up for the minimum time specified by the manufacturer Line power The Model 2520 requires a line voltage of 100V to 240V at line frequency of 50 or 60Hz The instrument must be calibrated while operating from a line voltage within this range Calibration considerations When performing the calibration procedures e Make sure that the test equipment is properly warmed up and connected to the Model 2520 input or output terminals as required Allow signals to settle before calibrating each point Do not connect test equipment to the Model 2520 through a scanner or other switching equipment e If an error occurs during calibration the Model 2520 will generate an appropriate error message See Appendix B for more information WARNING The maximum common mode voltage voltage between LO and chassis ground is 10V DC Exceeding this value may cause a shock hazard Model 25
121. n the 500mA range Limits are cal culated from one year current source accuracy specifications as follows Accuracy of setting offset 0 2 x 200mA 0 45mA 0 4mA 0 45mA 0 85mA Thus the actual source current range is 200mA 0 85mA or from 199 15mA to 200 85mA Calibration Reference B 2 Calibration Reference Introduction Model 2520 Pulsed Laser Diode Test System Service Manual This appendix contains detailed information on the various Model 2520 remote calibration commands calibration error messages and methods to detect the end of each calibration step Section 2 of this manual covers detailed calibration procedures Command summary Table B 1 summarizes Model 2520 calibration commands These commands are covered in detail in the following paragraphs Table B 1 Calibration commands Command Description CALibration Calibration subsystem PROTected Calibration commands protected by password CODE lt password gt Unlock calibration Default password KI002520 CODE Query calibration code password SENSe 1 lt NRf gt Calibrate active voltage measurement range DATA Query voltage measurement calibration constants SENSe2 lt NRf gt Calibrate active detector I current measurement range DATA Query detector I current measurement calibration constants SENSe3 lt NRf gt Calibrate active detector 2 current measurement range DATA Query detector 2 current measurement calibration
122. n voltage 5V 5 0000 V 10V 10 0000V 2 12 Calibration 10 11 12 Figure 2 2 Model 2520 Pulsed Laser Diode Test System Service Manual Connect the calibrator to the Model 2520 testhead VOLTAGE SENSE jacks as shown in Figure 2 2 Connect calibrator HI to VOLTAGE SENSE LO connect calibrator LO to VOLTAGE SENSE HI Turn on the calibrator output set the calibrator voltage to 10 000V then press ENTER The unit will prompt you as follows VL CAL Switch HI and LO connections Switch the HI and LO calibrator connections then press ENTER Press EXIT to return to normal display Press the LASER V key to make sure the laser volts mode is selected Press the RANGE Y key to select the 5V range Repeat steps 2 through 9 for the 5V range Be sure to set the calibrator output to 5 000V as shown in Table 2 4 Voltage measurement calibration connections Model 2520 Testhead Calibrator 0 utput DC Voltage BNC Cables 9o VOLTAGE VOLTAGE SENSE HI SENSE L Output LO Step 3 Current source calibration Follow the steps below to calibrate the current source Table 2 5 summarizes calibration resistors 1 From normal display press the Model 2520 LASER Vj key then set the range to 10V range using the RANGE A key Press the LASER I key press the EDIT ke
123. ng calibration command using the current calculated in step I 1 CAL PROT SO UR1 Calculated Current For example if the resistance value is 14 02Q and the returned voltage reading from step 10 is 0 6732V the actual current is I 0 6732V 14 02Q 0 048017A In this example the calibration command is CAL PROT SOUR1 0 048017 Send this command to source 90 of full scale current SO UR1 CURR 0 45 Repeat steps 9 through 12 Send this command to select the slow transition pulse SO UR1 PULS TRAN STAT ON Model 2520 Pulsed Laser Diode Test System Service Manual Calibration 2 27 Table 2 10 Remote current source calibration summary Current range Calibration resistance Calibration commands N A SOUR 1 FUNC SHAP PULS SENS 1 VOLT POL POS SOUR1 CURR POL POS 500mA 10 to 150 SOURI PULS TRAN STAT ON OFF SENS1 VOLT RANG 10 SOUR1 CURR RANG 0 5 OUTP1 ON DIAG KEIT BITS VDACI 4095 SOUR1 CURR 0 05 INIT SENS1 DATA CAL PROT SOUR1 Calculated Current SOUR1 CURR 0 45 INIT SENS1 DATA CAL PROT SOUR1 Calculated Current OUTP1 OFF 5A 1 2 to 1 60 SOUR 1 PULS TRAN STAT ON OFF SENS1 VOLT RANG 10 SOUR 1 CURR RANG 5 OUTP1 ON DIAG KEIT BITS VDAC1 4095 SOUR1 CURR 0 5 INIT SENS1 DATA CAL PROT SOUR1 Calculated Current SOUR1 CURR 4 5 INIT SENS1 DATA CAL PROT SOUR1 Calculated Current OUTP1 OFF 1 Use characterized resistance v
124. nrrnnnnrenrrnrnnrsnrsesvnssnnsnr September 2001 All Keithley product names are trademarks or registered trademarks of Keithley Instruments Inc Other brand names are trademarks or registered trademarks of their respective holders Safety Precautions The following safety precautions should be observed before using this product and any associated in strumentation Although some instruments and accessories would normally be used with non hazardous voltages there are situations where hazardous conditions may be present This product is intended for use by qualified personnel who recognize shock hazards and are familiar with the safety precautions required to avoid possible injury Read the operating information carefully before using the product The types of product users are Responsible body is the individual or group responsible for the use and maintenance of equipment for ensuring that the equipment is operated within its specifications and operating limits and for ensuring that operators are adequately trained Operators use the product for its intended function They must be trained in electrical safety procedures and proper use of the instrument They must be protected from electric shock and contact with hazardous live circuits Maintenance personnel perform routine procedures on the product to keep it operating for example setting the line voltage or replacing consumable materials Maintenance procedures are described in the
125. nts GmbH Flat 2B WILOCRISSA 14 Rest House Crescent Bangalore 560 001 91 80 509 1320 21 Fax 91 80 509 1322 ITALY Keithley Instruments s r l Viale S Gimignano 38 20146 Milano 02 48 39 16 01 Fax 02 48 30 22 74 NETHERLANDS Keithley Instruments B V Postbus 559 4200 AN Gorinchem 0183 635333 Fax 0183 630821 SWITZERLAND Keithley Instruments SA Kriesbachstrasse 4 8600 D bendorf 01 821 94 44 Fax 01 820 30 81 TAIWAN Keithley Instruments Taiwan 1 Fl 85 Po Ai Street Hsinchu Taiwan R O C 886 3572 9077 Fax 886 3572 903 4 01 Model 2520 Pulsed Laser Diode Test System Service M anual 2001 Keithley Instruments Inc All rights reserved Cleveland Ohio U S A First Printing September 2001 Document Number 2520 902 01 Rev A Manual Print History The print history shown below lists the printing dates of all Revisions and Addenda created for this manual The Revision Level letter increases alphabetically as the manual undergoes subsequent updates Addenda which are released between Revisions contain important change information that the user should incorporate immediately into the manual Addenda are numbered sequentially When a new Revision is created all Addenda associated with the previous Revision of the manual are incorporated into the new Revision of the manual Each new Revision includes a revised copy of this print history page Revision A Document Number 2520 902 01 rrrnrrrenrrrrnnrr
126. output check one Drifts C Unable to zero C Unstable Overload C Will not read applied input C Calibration only CJ Certificate of calibration required C Data required attach any additional sheets as necessary Show a block diagram of your measurement including all instruments connected whether power is turned on or not Also describe signal source Where is the measurement being performed factory controlled laboratory out of doors etc What power line voltage is used Ambient temperature SF Relative humidity Other Any additional information If special modifications have been made by the user please describe Be sure to include your name and phone number on this service form TEquipment BE USA NET An Interworld Highway LLC Company Specifications are subject to change without notice All Keithley trademarks and trade names are the property of Keithley Instruments Inc All other trademarks and trade names are the property of their respective companies KEITHLEY Keithley Instruments Inc BELGIUM Keithley Instruments B V CHINA Keithley Instruments China FRANCE Keithley Instruments Sarl GERMANY Keithley Instruments GmbH GREAT BRITAIN Keithley Instruments Ltd INDIA Keithley Instruments GmbH ITALY Keithley Instruments s r l KOREA Keithley Instruments Korea NETHERLANDS Keithley Instruments B V SWITZERLAND Keithley Instruments SA TAIWAN Keithley
127. output queue and test for an ASCII 1 3 After reading the output queue repeatedly test MAV again until it clears At this point the calibration step is completed Model 2520 Pulsed Laser Diode Test System Service Manual Calibration Reference B 11 U sing the 0 PC command The OPC operation complete command can also be used to detect the completion of each calibration step In order to use OPC to detect the end of each calibration step do the following 1 Enable operation complete by sending ESE 1 This command sets the OPC oper ation complete bit in the standard event enable register allowing operation com plete status from the standard event status register to set the ESB event summary bit in the status byte when operation complete is detected Send the OPC command immediately following each calibration command For example CAL PROT SOUR2 20 0 PC Note that you must include the semicolon to separate the two commands and that the OPC command must appear on the same line as the calibration command After sending a calibration command repeatedly test the ESB Event Summary bit bit 5 in the status byte until it is set Use STB to request the status byte Once operation complete has been detected clear OPC status using one of two methods 1 use the ESR query then read the response to clear the standard event status register or 2 send the CLS command to clear the status registers Note that sending
128. powers the output stage Regulated circuits include 5VFA 12VF 12VD and 25VF supplies to power the various circuits throughout the instrument Figure 4 3 Power supply block diagram Current M Source Analog Circuits O utput Digital Stage Circuits 5V 8V 12V 25V 5VD 12VD Analog Supplies Line In Line Power 100 240V AC Filter Transformers 4 10 Troubleshooting Model 2520 Pulsed Laser Diode Test System Service Manual Digital circuitry Refer to Figure 4 4 for the following discussion on digital circuitry Microcontroller The core digital circuitry uses a Motorola 68332 microcontroller U15 running at 16 78MHz The memory configuration includes a flash EEPROM U3 and U4 and a RAM U2 and U17 Flash ROM support allows internal firmware upgrades using either the serial or GPIB port for downloading new firmware All calibration constants and the saved setups are stored in a separate serial EEPROM U13 I O circuits External communication is provided via GPIB and serial interfaces A 9914 GPIB TEEE 488 standard interface IC is used for the GPIB US and an IC U20 provides the voltage conversion for the RS 232 port U35 provides interfacing for the Digital I O port while U46 and Q6 Q11 provide Trigger Link I O interfacing Digital signal processor U47 is the DSP IC that processes raw voltage and current samples into final readings Voltage and current data for the DSP is read from the high speed FIFO fir
129. procedure 2 23 Removing power components 5 6 Power module removal 5 6 Power supply module removal 5 6 Repair considerations 4 2 Resetting the calibration password 2 8 Restoring factory defaults 1 6 Routine Maintenance 3 1 Safety considerations 4 2 Specifications A 1 Static sensitive devices 5 3 Testhead connections 1 8 2 10 Testhead disassembly 5 7 Case disassembly 5 7 Input board removal 5 7 Output board removal 5 7 Testhead re assembly 5 7 Troubleshooting 4 1 4 12 Analog circuitry checks 4 15 Digital circuitry checks 4 14 Display board checks 4 12 Power supply checks 4 13 Unlocking calibration 2 7 by remote 2 7 from the front panel 2 7 Verification limits 1 6 Example limits calculation 1 6 Verification test requirements 1 4 Environmental conditions 1 4 Line power 1 4 Warm up period 1 4 Viewing calibration dates and calibration count 2 9 Voltage bias source accuracy 1 13 Voltage bias source commands B 8 DATA B 9 SOURce B 8 Voltage measurement accuracy 1 9 KEITHLEY Service Form Model No Serial No Date Name and Telephone No Company List all control settings describe problem and check boxes that apply to problem A Intermittent C Analog output follows display C Particular range or function bad specify IEEE failure C Obvious problem on power up CJ Batteries and fuses are OK C Front panel operational U All ranges or functions are bad C Checked all cables Display or
130. racy If the Model 2520 is not within specifications and not under warranty see the calibration procedures in Section 2 Calibration for information on calibrating the unit Test considerations When performing the verification procedures Restore factory front panel defaults as previously outlined Ensure test equipment is fully warmed up and properly connected to the correct Model 2520 terminals as required Allow signals to settle before making a measurement Do not connect test equipment to the Model 2520 through a scanner multiplexer or other switching equipment WARNING The maximum common mode voltage voltage between LO and chassis ground is 10V DC Exceeding this value may cause a shock hazard 1 8 Performance Verification Model 2520 Pulsed Laser Diode Test System Service Manual Testhead connections The Model 2520 mainframe must be connected to the testhead in order to perform the ver ification procedures Using Figure 1 1 as a guide make testhead connections as follows CAUTION Make sure power is turned off before making connections Connect mainframe TESTHEAD CONN 1 to testhead MAINFRAME CONN 1 Connect mainframe TESTHEAD CONN 2 to testhead MAINFRAME CONN 2 e Short pins 1 and 9 of the REMOTE INTERLOCK connector Insert the key in the KEY INTERLOCK and rotate to the ENABLED position to enable operation WARNING Shorting the interlock connector will disable the interlocks Use cau tion when perform
131. ration step from the front panel press the EXIT key To abort a calibration step via remote send the ABORt command 2 10 Calibration Model 2520 Pulsed Laser Diode Test System Service Manual Testhead connections The Model 2520 mainframe must be connected to the testhead in order to perform calibra tion Using Figure 2 1 as a guide make testhead connections as follows CAUTION Make sure power is turned off before making connections Connect mainframe TESTHEAD CONN 1 to testhead MAINFRAME CONN 1 Connect mainframe TESTHEAD CONN 2 to testhead MAINFRAME CONN 2 e Short pins 1 and 9 of the REMOTE INTERLOCK connector Insert the key in the KEY INTERLOCK and rotate to the ENABLED position to enable operation WARNING Shorting interlock connectors will disable the interlock Use caution to avoid live contacts when performing calibration NOTE Both interlocks must be enabled to perform calibration Figure 2 1 Testhead connections Model 2520 Mainframe M odel 2520 Testhead E Minne p wwe 4 BOTH INTERLOCKS MUST BE ENABLED TO OPERATE Klev Ce i Ld T Cr aao a g DE 9 Em E D Jo kr CONN 2 Cable CONN 1 Cable Front panel calibration The front panel calibration procedure described below calibrates all functions Note that each function and range is separately calibrated and the procedure must be performed in the order shown Model 2520 Pulsed Laser Diode Test System Service Manual Cali
132. rify that Model 2520 detector voltage bias source accuracy is within specified limits This test involves setting the bias voltages to specific values and measuring the voltages with a DMM 1 With the power off connect the digital multimeter to the Model 2520 testhead DETECTOR 1 jack as shown in Figure 1 6 2 Turn on the Model 2520 and DMM and allow them to warm up for a minimum of one hour 3 Restore BENCH defaults as covered previously in Restoring factory defaults Select the DMM DC volts measuring function and choose auto range Figure 1 6 Connections for DETECTOR 1 voltage bias source verification tests Model 2001 DMM Input HI M odel 2520 Testhead Inner Shield Conductor Input LO DETECTOR 1 1 14 Performance Verification Model 2520 Pulsed Laser Diode Test System Service Manual 5 Press the DETECTOR 1 Vy key press EDIT then set the source voltage to 20 000V using the EDIT A and W or numeric keys Press the ON OFF OUTPUT key to turn on the outputs then press TRIG Verify the DMM reading is within the following limits 19 75 to 20 25V Press the ON OFF OUTPUT key to turn off the outputs Repeats steps 5 through 8 for the DETECTOR 2 bias source make connections to the testhead DETECTOR 2 jack as shown in Figure 1 7 and use the DETECTOR 2 Vp key to set the output voltage oo uo Figure 1 7 Connections for D ETECTOR 2 voltage bias source verification tests HI M odel
133. rot lock cal prot lock 0 Calibration unlocked 1 Calibration locked The LOCK command allows you to lock out calibration after complet ing the procedure Thus LOCK performs the opposite of sending the password with the CODE command The LOCK query returns cali bration lock status To unlock calibration send the CODE command with the appropriate password CAL PROT LOCK Lock out calibration CALibration PRO Tected SAVE Purpose Format Description Note Example To save calibration constants in EEROM after the calibration procedure cal prot save The SAVE command stores internally calculated calibration constants derived during comprehensive in EEROM EEROM is non volatile memory and calibration constants will be retained indefinitely once saved Generally SAVE is sent after all other calibration steps except for LOCK Calibration will be only temporary unless the SAVE command is sent to permanently store calibration constants Calibration data will not be saved if calibration was not unlocked by sending the CODE command or if invalid calibration data exists CAL PROT SAVE Save calibration constants Model 2520 Pulsed Laser Diode Test System Service Manual Calibration Reference B 5 DATE C ALibration PRO Tected D ATE Purpose Format Parameters Query Response Description Note Example NDUE CALibration PRO Tected N D U E Purpose Format Parameters
134. rs or limit repairs to the PC board replace ment level Without proper equipment and training you could damage a PC board beyond repair Repairs will require various degrees of disassembly However it is recommended that the Front Panel Tests be performed prior to any disassembly The disassembly instructions for the Model 2520 are contained in Section 5 of this manual Do not make repairs to surface mount PC boards unless equipped and qualified to do so see previous CAUTION e When working inside the unit and replacing parts be sure to adhere to the handling precautions and cleaning procedures explained in Section 5 Many CMOS devices are installed in the Model 2520 These static sensitive devices require special handling as explained in Section 5 e Whenever a circuit board is removed or a component is replaced the Model 2520 must be recalibrated See Section 2 for details on calibrating the unit Power on self test During the power on sequence the Model 2520 will perform a checksum test on its EPROM and test its RAM If one of these tests fails the instrument will lock up Model 2520 Pulsed Laser Diode Test System Service Manual Troubleshooting 4 3 Front panel tests There are three front panel tests one to test the functionality of the front panel keys and two to test the display In the event of a test failure refer to Display board checks for details on troubleshooting the display board KEYS test The KEYS test
135. s Aa 428 303D REAR BEZEL BOTTOM CHASSIS COVER REF USED ON FA 232 1C 2 CAPTIVE PA EL SCREW EM DIMENSIONAL TOLERANCES MC 233A WARNING LABEL DO NOT SCALE THIS DRAWING UNLESS OTHERWISE SPECIFIED SE MC 285 SERIAL NUMBER XX 015 ANG f poets EEE KEITHLEY fide ones mn Am FRAC Ae CEET CABLE SURFACE MAX if 0890 0262 LTRIECA NO REVISION ENG DATE C 25949 Add PA s amp Manual s To Part List ST 7 11 01 can CI 26087 CA 290 1B Was CA 290 1A Recommended Procedure 1 Turn the UUT ON 2 Verify all display segments and annunciators turn ON for a few seconds 3 Verify Firmware Rev 4 Verify GPIB Address 25 5 Verify that front panel displays zero for Ipulse and dashes for Current and Voltage To change GPIB Address 1 Press COMM 2 Using the Left and Right Arrow Keys Select GPIB and Press ENTER 3 Using UP and DOWN Arrow Keys set Address to 25 and Press ENTER 4 Using the LEFT and RIGHT Arrow Keys Select SCPI and Press enter 5 To EXIT Press EXIT 2520 052 CHASSIS ASSEMBLY 428 329F HANDLE NOTE KEEP THE 2520 UNIT AND 2520 300 TEST HEAD ASSEMBLY MATCHED FROM TECH MUST BE SHIPPED TOGETHER NOTE PLACE THE 2 CABLES FROM TECH IN THE WORK ORDER SHIPPING KIT BAGC PLACE CERTIFICATE OF CALIBRATION ON TOP OF UNIT THEN PLACE INTO PO 14 4 2 PLACE SWITCH KEY IN THE 8 X 10 CHIPLOC BAG AND SEND WITH W O SHIPPING KIT IT
136. s or more including the com bined effect of normal and common mode voltages Use standard safety precautions to avoid personal contact with these voltages The WARNING heading in a manual explains dangers that might result in personal injury or death Always read the associated information very carefully before performing the indicated procedure The CAUTION heading in a manual explains hazards that could damage the instrument Such damage may invalidate the warranty Instrumentation and accessories shall not be connected to humans Before performing any maintenance disconnect the line cord and all test cables To maintain protection from electric shock and fire replacement components in mains circuits including the power transformer test leads and input jacks must be purchased from Keithley Instruments Standard fuses with applicable national safety approvals may be used if the rating and type are the same Other components that are not safety related may be purchased from other suppliers as long as they are equivalent to the original component Note that selected parts should be purchased only through Keithley Instruments to maintain ac curacy and functionality of the product If you are unsure about the applicability of a replacement component call a Keithley Instruments office for information To clean an instrument use a damp cloth or mild water based cleaner Clean the exterior of the instrument only Do not apply cleaner direc
137. sending the calibration password as explained in the following paragraphs Unlocking calibration from the front panel 1 Press the MENU key then choose CAL and press ENTER The instrument will display the following CALIBRATION UNLOCK EXECUTE VIEW D ATES p gt SAVE LOCK CHAN GE PASSW ORD 2 Select UNLOCK then press ENTER The instrument will display the following PASSWORD Use lt P A Y ENTER or EXIT 3 Use the EDIT A and Y keys to select the letter or number and use the EDIT a and p arrow keys to choose the position Press A for letters W for numbers Enter the present password on the display Front panel default 002520 4 Once the correct password is displayed press the ENTER key You can then pro ceed with the calibration procedure Unlocking calibration by remote To unlock calibration via remote send the following command CAL PROT CODE lt password gt For example the following command uses the default password CAL PROT CODE KI002520 2 8 Calibration Model 2520 Pulsed Laser Diode Test System Service Manual Changing the password The default password 002520 may be changed from the front panel or via remote as discussed below Changing the password from the front panel Follow the steps below to change the password from the front panel 1 Press the MENU key choose CAL and press ENTER The instrument will display the following CALIBRATION UNLOCK EXECUTE VIEW D ATES p gt S
138. st in first out SRAM circuits U27 U29 U38 U42 and U49 after being stored there by the A D converters Display board circuits The display board includes a microcontroller U902 that controls the VFD vacuum fluo rescent display and interprets key data The microcontroller has four peripheral I O ports that are used for the various control and read functions The VFD vacuum fluorescent display module DS901 can display up to 49 characters Each character is organized as a 5 x 7 matrix of dots or pixels and includes a long under bar segment to act as a cursor The display uses a common multiplexing scheme with each character refreshed in sequence Circuitry includes the grid drivers and dot drivers Model 2520 Pulsed Laser Diode Test System Service Manual Troubleshooting 4 11 Figure 4 4 Digital circuitry block diagram ROM RAM U3 U4 U2 U17 Serial Interface RS 232 Interface U20 E PROM U13 GPIB EES IEEE 488 Interface U15 U5 U6 U19 DSP Land To Display Board Controller Data From A D 16 78MHz Converters Trigger Trigger U 46 Link Q6 Q11 To Current and Voltage Digital 1 0 T Source Control DACs gary U 35 4 12 Troubleshooting Model 2520 Pulsed Laser Diode Test System Service Manual Troubleshooting Troubleshooting information for the various circuits is summarized below Refer to the component layout drawings at the end of Section 6 for component locations Display board checks
139. sts and procedures covered in this section of the manual Refer to the following drawings Figure 4 1 Overall block diagram Figure 4 2 Analog circuitry block diagram Figure 4 3 Power supply block diagram Figure 4 4 Digital circuitry block diagram Overall block diagram Figure 4 1 shows an overall block diagram of the Model 2520 Circuitry may be divided into two general areas Analog circuits includes measurement circuits for voltage and I V converter for current A D converters and voltage bias and current source circuits Digital circuits includes the microcomputer that controls the analog section front panel and GPIB and RS 232 ports the DSP digital signal processor and associated interfacing and data storage circuits Model 2520 Pulsed Laser Diode Test System Service Manual Troubleshooting 4 5 Figure 4 1 Overall block diagram GPIB M RS 232 MC68332 Digital 1 0 2 Line VFD Microprocessor gt Trigger Link Front Panel Keypad DSP Voltage Source Detector 1 20V 100mA Max SRAM I V Converter Detector 1 4 Current Ranges Voltage Source Detector 2 20V 100mA M ax IV Converter Detector 2 Va 4 Current Ranges DETECTOR 2 Laser Diode Current Source 10V DC PU LSED 5A 9V Pulse OUT Voltage M easurement PULSED 2 Voltage Ranges SEN SE DETECTOR 1 4 6 Troubleshooting Model 2520 Pulsed Laser Diode Test System Service Manual Analog circuits
140. t calibration Follow these steps to calibrate current measurements for both photodiode detector chan nels Table 2 13 summarizes calibration currents and commands 1 2 Select the DMM DC voltage function and enable auto range Temporarily short the ends of the DMM test leads together and enable the REL mode to null offsets Connect the DMM and 2kQ resistor to the Model 2520 testhead DETECTOR 1 jack as shown in Figure 2 7 Send the following command to select the 10mA range SEN S2 CURR RANG 10e 3 Put the unit into the DC mode SOUR1 FUNC SHAP DC Select positive current measurement polarity SEN SE2 CU RR POL POS 2 32 Calibration 10 11 12 13 14 15 16 17 18 19 20 21 Model 2520 Pulsed Laser Diode Test System Service Manual Send this command to turn on the outputs OUTP1 ON Send the following command to output 20V SO UR2 VOLT 20 Note the DMM voltage reading then calculate the current from the characterized resistance value and DMM voltage reading I V R Send the following command to calibrate the negative full range current point CAL PRO T SEN S2 Calculated current Send the following command to output OV SOUR2 VOLT 0 Note the DMM voltage reading then calculate the current from the characterized resistance value and DMM voltage reading I V R Send the following command to calibrate the zero range current point CAL PRO T SEN S2 Calc
141. tains replacement parts information and component layout drawings for the Model 2520 Pulsed Laser Diode Test System Parts lists The electrical parts lists for the Model 2520 are shown in tables at the end of this section For part numbers to the various mechanical parts and assemblies use the Miscellaneous parts list and the assembly drawings provided at the end of Section 5 Ordering information To place an order or to obtain information concerning replacement parts contact your Keithley representative or the factory see inside front cover for addresses When order ing parts be sure to include the following information Instrument model number Model 2520 Instrument serial number e Part description Component designation if applicable e Keithley part number Factory service If the instrument is to be returned to Keithley Instruments for repair perform the following Callthe Repair Department at 1 800 552 1115 for a Return Material Authorization RMA number Complete the service form at the back of this manual and include it with the instrument e Carefully pack the instrument in the original packing carton Write ATTENTION REPAIR DEPARTMENT and the RMA number on the shipping label Component layouts The component layouts for the circuit boards are provided on the following pages Model 2520 Pulsed Laser Diode Test System Service Manual Replaceable Parts 6 3 Table 6 1 Mainframe dig
142. ting screws Remove the five mounting screws that secure the motherboard to the chassis Model 2520 Pulsed Laser Diode Test System Service Manual Disassembly 5 5 3 Unplug cables e Unplug the ribbon cables from J1007 and J1033 e Unplug the cable going to the power supply module from J1011 e Unplug the cable going to the OUTPUT indicator from J1034 e Unplug the wires going to the rear panel PULSE SYNC OUT jack from J1006 Remove the motherboard Slide the motherboard forward slightly until the rear panel connectors clear the holes in the rear panel then remove the board During re assembly replace the motherboard and start the IEEE 488 DIGITAL I O RS 232 and TESTHEAD CONNI connector screws and the board mounting screws Tighten all the fasteners once they are all in place and the board is correctly aligned Be sure to plug in all cables Front panel disassembly Use the following procedure to remove the display board and or the push button switch pad 1 Remove the front panel assembly This assembly has four retaining clips that snap onto the chassis over four pem nut studs Two retaining clips are located on each side of the front panel Pull the retaining clips outward and at the same time pull the front panel assembly forward until it separates from the chassis Unplug the display board ribbon cables Using a thin bladed screwdriver pry the plastic PC board stop located at the bot tom of the display board until th
143. tion resistor 10mA 2kQ 20mA 1kQ 50mA 4000 100mA 2000 Nominal values Use measured values for procedure 1 Select the DMM DC volts function and enable auto range Temporarily short the ends of the DMM test leads together then enable REL to null offsets 2 Connect the 2kQ resistor and the DMM to the Model 2520 testhead DETECTOR 1 jack as shown in Figure 2 7 3 From normal display press the Model 2520 DETECTOR 1 Ipp key then select the 10mA current range using the RANGE y key Press the MENU key select CAL then press ENTER Select EXECUTE then press ENTER to enter the CAL EXECUTION menu Select Ipd1 then press ENTER The instrument will prompt for the resistor value RES VALUE 2000 00 Use 4 gt A V ENTER or EXIT amp Figure 2 7 Detector 1 current measurement calibration connections Input HI Center Conductor Model 2520 Testhead G 20 00000000 9 9 0 ED E Inner E x Shield 0 K Resistor rant b s See Text Input LO DETECTOR 1 Model 2520 Pulsed Laser Diode Test System Service Manual Calibration 2 19 7 Press ENTER The instrument will prompt for calibration with 20V Ipd 1 CAL Press ENTER to Output 20 000 V 8 Press ENTER The unit will display DMM RDG 20 000 V Use 4 gt A V ENTER or EXIT 9 Use the EDIT keys to adjust the Model 2520 display value to agree with the DMM voltage reading 10 Press ENTER The instru
144. tly to the instrument or allow liquids to enter or spill on the instrument Prod ucts that consist of a circuit board with no case or chassis e g data acquisition board for installation into a computer should never require cleaning if handled according to instructions If the board becomes contami nated and operation is affected the board should be returned to the factory for proper cleaning servicing Rev 2 01 Table of Contents 1 Performance Verification Introduction 5 3 itn erem t ets 1 2 Verification test requirements ooooooccoccconcnconnconcnonnncnnccconeconncnancn no 1 4 Environmental conditions esse 1 4 Warm up period sess 1 4 Eine POWER Pm 1 4 Recommended test equipment sse 1 5 Resistor characterization essere 1 5 Verification HNS s oiii eet eerbeseit vein ctis retire dieit ede edo 1 6 Example limits calculation eee 1 6 Restoring factory defaults sse 1 6 Performing the verification test procedures 1 7 Test summary eeeeeeeeeeee enne nennen enne nnne rennen 1 7 Test considerations esses 1 7 Testhead connections sese 1 8 Voltage measurement accuracy sseeeeeen nee 1 9 Current source accuracy msenrnrrvvrrvvevvervrevverrrevveevrevrarvravvaresesnsee 1 10 Current measurement accuracy ssesseeeeeeeeneee
145. tom 5 Pullthe input board forward until the MAINFRAME CONN 1 connector clears the rear panel then carefully remove the input board from the case bottom Testhead re assembly Re assemble the testhead by reversing the above procedure Be sure that all cables are connected and that all screws standoffs and nuts are installed and properly secured 07 0 02 ON SLEP 11 6430 3134 OVERLAY 7 MEMBRANE SWITCH 2520 3064 FRONT PANEL o 2520 004 PL 94 ASSEMB he FLAT SIDE A GM Ou LENS LED ei 2520 31 14A o REF FRONT PANE P4 MASK FROM THE LENS DISPLAY LENS DO NOT REMOVE THE GREEN 2400 110D 7 L 2520 315A CONDUCTIVE STEP 2 RUBBER SWITCH DISPLAY BOARD ASSEMBLY SNAP TOP OF BOARD INTO FRONT PANEL LTRIECA NO REVISION ENG DATE A Released 2001 371A P C BOARD STOP 2 REQ D PLACE ON FRONT PANEL TABS AND SLIDE TOWARDS OUTSIDE EDGE OF PANEL CA 239 3A CABLE PART NUMBER QTY DESCRIPTION 2520 3064 FRONT PANEL 2400 1100 DISPLAY BOARD ASSEMBLY 6430 313A OVERLAY MEMBRANE SWITCH 2520 3114 DISPLAY LENS 2520 3154 CONDUCTIVE RUBBER SWITCH 2001 371A 2 P C BOARD STOP 6517 3098 LENS LED 2520 004 CRIMP ASSEMBLY CA 239 3A CABLE T DIMENSIONAL TOLERANCES DO NOT
146. uct must be protected from electric shock at all times The responsible body must en sure that users are prevented access and or insulated from every connection point In some cases con nections must be exposed to potential human contact Product users in these circumstances must be trained to protect themselves from the risk of electric shock If the circuit is capable of operating at or above 1000 volts no conductive part of the circuit may be exposed Do not connect switching cards directly to unlimited power circuits They are intended to be used with impedance limited sources NEVER connect switching cards directly to AC mains When connecting sources to switching cards install protective devices to limit fault current and voltage to the card Before operating an instrument make sure the line cord is connected to a properly grounded power re ceptacle Inspect the connecting cables test leads and jumpers for possible wear cracks or breaks be fore each use When installing equipment where access to the main power cord is restricted such as rack mounting a separate main input power disconnect device must be provided in close proximity to the equipment and within easy reach of the operator For maximum safety do not touch the product test cables or any other instruments while power is applied to the circuit under test ALWAYS remove power from the entire test system and discharge any capacitors before connecting or disconnecting
147. ulated current Switch current measurement polarity to negative SEN SE2 CU RR PO L NEG Calibrate the negative zero range current point CAL PRO T SEN S2 Calculated current Send the following command to output 20V SOURL VOLT 20 Note the DMM voltage reading then calculate the current from the characterized resistance value and DMM voltage reading I V R Send the following command to calibrate the positive full range current point CAL PRO T SEN S2 Calculated current Note that if the measured voltage is negative the current will be negative Repeat steps 4 through 18 for the 20mA 50mA and 100mA ranges using Table 2 13 as a guide Be sure to e Select the appropriate range using the SENS2 CURR RANG Range command Send the appropriate calibration current values with the CAL PROT SENS2 Current command Turn off the outputs by sending OUTP1 OFF Repeat steps 3 through 20 for the other photodiode current measurement channel Be sure to Connect the DMM and resistor to the testhead DETECTOR 2 jack Figure 2 8 Use the SOUR3 CURR RANG command to select the correct range Use the CAL PROT SOUR3 command for each calibration point Model 2520 Pulsed Laser Diode Test System Service Manual Calibration 2 33 Table 2 13 Remote current measurement calibration currents and commands Calibration Channel Current range Test resistor currents Calibration commands Detector 1 10mA 2KQ OUTP1 O
148. voltage cal prot sens2 Cal current cal prot sens3 Cal current Parameters Cal current Within 10 of positive full range value Cal voltage 00 1 of full range value Within 10 of negative full range value Description The CAL PROT SENSI command calibrates the active voltage mea surement range while the CAL PROT SENS2 and CAL PROT SENS3 commands calibrate the active detector 1 or detector 2 current measure ment range respectively During the calibration process each command is sent three times for each range once each with parameters of positive full range 0 and negative full range The appropriate calibration voltage or current must be applied to the appropriate input terminals Example CAL PROT SENS2 20e 3 Calibrate detector I 20mA range DATA CALibration PRO Tected SEN Se 1 D ATA C ALibration PRO Tected SEN Se2 D ATA C ALibration PRO Tected SEN Se3 D ATA Purpose To query measurement calibration constants Query cal prot sensl data cal prot sens2 data cal prot sens3 data Description The CAL PROT SENS1 DATA query requests voltage calibration constants while the CAL PROT SENS2 DATA and CAL PROT SENS3 DATA queries request calibration current con stants for detector 1 and detector 2 respectively Returned values are in ASCII format separated by commas Example CAL PROT SENS1 DATA Query voltage constants Model 2520 Pulsed Laser Diode Test System Service Manual Ca
149. y then set the source to the 500mA range using the RANGE key Press the MENU key select CAL then press ENTER Select EXECUTE then press ENTER to enter the calibration menu Model 2520 Pulsed Laser Diode Test System Service Manual Calibration 2 13 5 Select IL then press ENTER The instrument will prompt for the resistor RES VALUE 15 000 Use lt gt A V ENTER or EXIT Table 2 5 Current source calibration values Current source range Calibration resistor 500mA 10 to 150 5A 1 2 to 1 60 6 Enter the measured value of the 10 to 15Q resistor then press ENTER The unit displays the following IL CAL Connect Calibration Resistor to p gt lt q Pulse Sense and Pulse Source 7 Connect the 10 to 15Q resistor to the Model 2520 testhead VOLTAGE SENSE and CURRENT OUTPUT jacks as shown in Figure 2 3 8 Press ENTER to complete calibration of the present range 9 Press EXIT to return to normal display 10 Press LASER I then EDIT then use the RANGE A key to select the 5A current range 11 Press LASER Vy then use the RANGE A key to make sure the 10V range is selected 12 Disconnect the 10 to 15Q resistor then connect the 1 2 to 1 6Q resistor in its place Figure 2 3 13 Repeat steps 3 to 9 for the 5A range using the 1 2 to 1 6Q resistor instead of the 10 to 15Q resistor Figure 2 3 Current source calibration connections Model 2520 Testhead 10 to 15Q Resistor 500mA Range 1 2 to 1 6Q Resistor 5
150. y radiation The test fixture interlock must not be defeated The testhead key control must be used to prevent operation unless authorized by the responsible body This requirement must be part of the facilities administrative controls for laser safety Outputs cannot be turned on with the key removed When servicing the test system any required personnel protection equipment e g laser safety goggles must be provided by the cus tomer s responsible body The customer s laser safety officer LSO must review and approve all installations before they are put into operation Any safety con cerns must be immediately reported to the customer s LSO If at any time the indicators provided on the testhead for INTER LOCK STATUS or LASER POWER ON should fail to light or properly indicate status immediately contact a Keithley service representative for repair Failure to do so may expose the user to hazards without proper warnings See Interlock status indicator test sequence in Section 9 of the User s manual for details on test ing the indicator lights Maximum isolation from earth ground is 10V Exceeding this value may result in a shock hazard When making connections do not leave any exposed connections Ensure that all external circuits are properly insulated 2 4 Calibration Model 2520 Pulsed Laser Diode Test System Service Manual Environmental conditions Temperature and relative humidity Conduct the calibratio

Model 2520 Pulsed Laser Diode Test System Service Manual

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