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576 user manual

1. 1 r ses a d a dA NT DOT 2 lt AE LIT ES B NK ja n W d LE F LL MASS LLL UNEIA LL Ip VS Vps for different values of Vas Some Common Measurements The static transconductance source grounded is Ip V qs The small signal transconductance source grounded is Alp 4AVGs To determine gm at various points in a family of curves multiply the vertical separation of two adjacent curves by the B OR gm PER DIV readout To make a more accurate measurement see steps 69 through 74 of the First Time Operation instructions b Ren Operating Instructions Type 576 IDSS Drain source current with zero VGs is measured from the common source family with the Terminal Selector switch set to BASE TERM SHORT It should be measured above the knee of the curve Pinch Off Voltage Vp Pinch off voltage Vp can be measured by increasing the depletion voltage with the OFFSET MULT control and the AMPLITUDE switch until the specified pinch off cur rent is reached by the zero step zero step only is obtained by pressing SINGLE button Thus the pinch off voltage is the setting of the OFFSET MULT control times the setting of the AMPLITUDE switch BVGSS Gate source breakdown voltage with the drain shorted to the source can be measured by putting the gate lead of the device in the drain terminal of the test socket the source lead in the gate terminal and the drain lead in the
2. INSTRUCTION MIAN UAL Seid Number Tektronix Inc 5 W Millikan Way amp P O Box 500 Beoverton Oregon 97005 Phone 44 0l Cables Tektranix 070 0905 00 269 INSIDE FRONT COVER Lis ll c MORIES gt tnt ive 75 VOLTMETER ip SE OUT 410 SWITCH PRINT COMMAND a x1 TI Fa zd E pamah i ate O gt X SERIES M MOCELI MES p ri M n ai da the z gt a E Ls E Mi Tang EEE G aa manda EE M ELIT LAE Fok a en LET OH TYPES DSFPLAY Ok DUE Ae i SEE PARTS SE D ai i ms E e he m ul ia nf e cil mi ct CE r FRA ah e E dart 4 D veu KT n 5 MT di Soe Te Fig 1 1 Type 576 Curve Tracer X SECTION 1 SPECIFICA TION Type 576 Change information if any affecting this section will be found at the rear of the manual The Type 576 Curve Tracer is a dynamic semiconductor tester which allows display and measurement of characteris tic curves of a variety of two and three terminal devices including bipolar transistors field effect transistors MOS FETs silicon controlled rectifiers and unijunction transis tors A variety of possible measurements is available using either grounded emitter or grounded base configurations The instrument has available either an AC or a DC collector supply voltage ranging from O to 1500 volts The step generator produces either current or v
3. current limiting is provided through the CURRENT LIMIT switch Mac d agi Fig 2 24 Step Generator output in both polarities The rate of generation of steps by the Step Generator is determined by the RATE buttons When the NORM RATE button is pressed steps are generated at a rate of 120 steps second assuming a 60 Hz line frequency or one step per cycle of the Collector Supply POLARITY switch set to NPN or PNP In this case each step occurs at the beginning of a Collector Supply cycle When the 5X RATE button is pressed the Step Generator rate is 60 steps AL second or one step per 2 cycles of the Collector supply Again each step occurs at the beginning of a Collector Supply cycle This rate should be used when the PO LARITY switch is set to AC Pressing the 2X RATE but ton produces a Step Generator rate of 240 steps second 2 steps per cycle of the Collector Supply In this case steps occur at both the beginning and the peak of a Collector Supply cycle If the 2X RATE and 5X RATE buttons are pressed together the Step Generator rate is the normal rate of 120 steps second except that the steps occur at the peak of each Collector Supply cycle rather than at the beginning as in normal rate operation The STEP FAMILY buttons determine whether step families are generated ropetitively or one family at a time Pressing the REP STEP FAMILY button turns the Step Generator on and provide
4. specification given in Section 1 the Performance Check and Calibration Procedure in Section b must be used 1 Apply power to the Type 5 6 2 Allow the instrument to warm up for a few minutes Instrument should operate within specified tolerances 5 minutes after it has been turned on 3 Set the Type 576 and Standard Test Fixture front panel controls as follows READOUT ILLUM Fully counterclockwise GRATICULE ILLUM Fully counterclockwise INTENSITY Fully counterclockwise FOCUS Centered VERTICAL 1 mA n i 4 DISPLAY OFFSET Selector CENTERLINE VALUE HORIZONTAL Vertical POSITION Vertical FINE POSITION Horizontal POSITION Horizontal FINE POSITION ZERO CAL DISPLAY INVERT MAX PEAK VOLTS PEAK POWER WATTS VARIABLE COLLEC TOR SUPPLY POLARITY MODE LOOPING COMPENSATION NUMBER OF STEPS CURRENT LIMIT AMPLITUDE OFFSET STEPS PULSED STEPS STEP FAMILY RATE POLARITY INVERT STEP MULT 1X Terminal Selector LEFT OFF RIGHT NORM OFF 0 1 V COLLECTOR Centered Centered Centered Centered Released Released Released 15 0 1 Fully Counterclockwise AC NORM As is 1 20 mA 0 5 LA ZERO Pressed Released REP ON NORM Released Released BASE TERM STEP GEN OFF Operating Instructions T ype 576 CRT and Readout Controls 4 Turn the GRATICULE ILLUM control throughout its range Note that the graticule lines become illuminated as the control is turned clockwise
5. turn the VARIABLE COLLECTOR SUPPLY control fully clockwise Note that the diagonal line obtained in step 16 does not appear When the yellow light is on the Collector Supply is disabled 24 Set the following Type 576 controls MAX PEAK VOLTS 79 VARIABLE COLLECTOR Fully counterclockwise SUPPLY LEFT OFF RIGHT OFF 25 Install the protective box on the Standard Test Fix ture as shown in Fig 2 7 26 Close the lid of the protective box and set the LEFT OFF RIGHT switch to RIGHT Note that the yellow light turns off and the red light turns on WARNING The red light indicates that dangerous voltages may appear at the collector terminals of the Standard Test Fixture 27 Turn the VARIABLE COLLECTOR SUPPLY con trol clockwise Note that the diagonal trace appears indica ting that the Collector Supply has been enabled i E 28 Set the following Type 576 controls to MAX PEAK VOLTS 15 VARIABLE COLLECTOR SUPPLY Fully Counterclockwise The protective box may be removed if desired 29 Turn the VARIABLE COLLECTOR SUPPLY con trol until the diagonal trace reaches the center of the CRT graticule Pull out on the PEAK POWER WATTS switch and set it to 220 Note that the diagonal trace lengthens as the switch is turned through its range Also note that the SERIES RESISTORS decrease as the maximum peak power Is increased 30 Allow the MAX PEAK VOLTS switch and the PEAK POWER WATTS switch to become interlocked and swi
6. 2 23 Operating Instructions T ype 576 2 24 TEST SET UP CHART TYPE 576 INTENSITY FOCUS VE RTI CA L CURRENT DIV TYPE 576 CURVE TRACER TEKTRONIX INC PORTLAND OREGON U 8 A WIPE ROD ae C FET SM OR Ep TEP PED CARS osrmon DISPLAY OFFSET NORM OFF MAGNIFIER HORIZONTAL VOLTS DIV DISPLAY a SN BASE 05 5 COLLECTOR ocu ee I ee a tet aig aes Nay yey oe Man EN CAMERA GRATICULE READOUT POWER ILLUM ILLUM 125V ERROR IN LEAKAGE MODE BELOW T4LA OIV A COLLECTOR SUPPLY POLARITY MODE NUMBER OF STEPS STEP GENERATOR 208A 00mA NORM CURRENT STEP OFFSET oc LIMIT AMPLITUDE ANTI LOOP S00 mA BAS 2 mA LEAKAGE E EMITTER CURRENT 2A i OFFSET MULT 0 10 LOOPING b STEP GEN POLARITY COMPENSATION UNLESS INVERTED O 14k FF STEP MULT SERIES 3k 850 OFFSET u SN POWER COLLECTOR SUPPLY GENG core caii i VOLTAGE DISABLED eee tts VERY RAFIDUY WITH INCAEASING VOLTAGE USE CURRENT LIMITS PULSED STEPS AUTO DC MODE FAMILY OFF RATE pev s STEPS STEP ON OFF C SERIAL O USE PROTECTIVE BOX EMITTER GROUNDED GEN OPEN BASE OR EXT TERM d ien P COLLECTOR SUPPLY RESET VARIABLE COLLECTOR SUPPLY PERCENT Of MAX PEAK VOLTS 40 60 LEFT OFF RIGHT RED LIGHT INDICATES DANGEROUS VOLTAGES MAY APPEAR AT COLLECTOR TERMINALS EXT BASE STEP GEN OR EMIT OUTPUT INP
7. 576 and device capacitance It may also be caused by heating of the device under test The LOOPING COMPEN SATION control provides complete compensation for non heat related looping due to the Type 5 6 and any standard device adapter which may be used In general it does not compensate for any added capacitance introduced by the device under test Control has some effect in reducing stray capacitance in small diodes and voltage driven three terminal devices If uncompensated looping is hindering measurements the MODE switch should be set to DC ANTILOOP If the collector sweep mode of operation MODE switch set to NORM is desired an imaginary line lying inside the loop and equidistant from each side of the loop is the best approximation of the actual characteristic curve see Fig 2 23 Looping due to heating may be re duced by using the pulsed steps operation of the Type 576 Best approximation 3 E of actual characteristic 4 L gt t 1 t i 1 t i t 1 1 1 b 1 A 1 L Fig 2 23 Example of a display exhibiting looping Interlock System Whenever the MAX PEAK VOLTS switch is in the 75 350 or 1500 positions the yellow COLLECTOR SUPPLY VOLTAGE DISABLED light comes on This light indicates that the Collector Supply is disabled In order to enable the Collector Supply under these circumstances the Type 576 uses an interlock system When the yellow light is on the 2 22 protecti
8. Centered VARIABLE COLLEC Fully Clockwise TOR SUPPLY MODE NORM LEFT OFF RIGHT LEFT 38 Adjust the LOOPING COMPENSATION control for minimum trace width see Fig 2 9 da m oh 4 Incorrect Adju NER NUBE PT Type ty AA ET da EXE SE A s correct adjustment Poke we A od i 1 t a 1 t t 7 t 1 4 t L 1 Fig 2 9 Adjustment of LOOPING COMPENSATION control 39 Set the following Type 576 controls to VERTICAL 5 mA Vertical POSITION Switch centered VARIABLE COLLEC Fully Counterclockwise TOI SUPE LY MODE AC LEFT OFF RIGHT OFF 2 11 Operating Instructions T ype 576 40 Remove the diode from the diode adapter and re place it with a 8 volt Zener diode Align the diode so that its cathode is connected to the emitter terminal 41 Set the LEFT OFF RIGHT switch to RIGHT and turn the VARIABLE COLLECTOR SUPPLY control clock wise Note that the display shows both the forward and reverse characteristics of the Zener diode see Fig 2 10 LLLLLALLLLI ijremara Bis Zener Breakdown TENS t ual i b t Q x ADMIN o N XZOIm n LINII LLLI ANE S MERE LU LL SE LLL Reverse Bias L 4 1 se 4 1 NIN Na a am Reo 23330 ume Fig 2 10 Display of Zener diode I vs V characteristic with PO LARITY switch set to AC Display Offset and Magnifier 42 Set the following Type 5 6 controls to HORIZONTAL 2 V COLLE
9. STEPS 1 OFFSET MULT 0 STEP MULT Released 76 Turn the OFFSET MULT control until a step just begins to appear on the CRT Note the multiplier value on the OFFSET MULT control This number times the AM PLITUDE switch setting is the base to emitter turn on volt age of the transistor 2 15 Operating Instructions T ype 576 e x Fi DME o LLL osie NA ae re saa WAH AA Des TF RET IAZCECELILI J 3 ELE LLLL 3 i KN E SD E PRI m mayang 1 y 1 era v E R T DIY PER H O R l z Div eee A LL LE LL LL EL LL LL E LLL LA NEERMMEEZEEEEX 5 To VMA A Oo 1uo5 m zi Fig 2 18 Measurement of of transistor A Coarse measurement B Offsetting of display and 1X multiplication of step amplitude C LOX magnification of vertical display Standard Test Fixture 77 Set the following Type 5 6 controls to AMPLITUDE 20 LA OFFSET ZERO 78 Note the display of the characteristic curves with the emitter grounded and the current steps applied to the base see Fig 2 19A 2 16 mm g e ST oma m ove 2237 PER V E R T g o 2wN z2orj3 B Common Base Family Fig 2 19 A Terminal Selector switch set to BASE TERM STEP GEN NORM B Terminal Selector switch set to EMITTER TERM STEP GEN 79 Set the LEFT OFF RIGHT switch to OFF and the STEP FAMILY button to OFF Take a patch cord with banana plugs on e
10. diode adapter and replace it with the universal transistor adapter Tektronix Part No 013 0098 00 49 Place an NPN silicon transistor into the right tran sistor test socket of the universal transistor adapter 50 Set the LEFT OFF RIGHT switch to RIGHT and turn the VARIABLE COLLECTOR SUPPLY clockwise un til the peak collector emitter voltage is about 10 volts 51 Turn the AMPLITUDE switch until a step appears on the CRT Note that the greater the step amplitude the greater the collector current see Fig 2 12 Set the AMPLI TUDE for the minimum step amplitude which produces a noticeable step in the display a e a m lt gun N 2OI 9 lt PER Fig 2 12 Collector current vs Collector Emitter voltage for various settings of the AMPLITUDE switch 52 Turn the NUMBER OF STEPS switch clockwise Be sure the PEAK POWER WATTS switch is set within the power dissipation rating of the transistor being used Note the display of collector current vs collector emitter voltage for ten different values of base current see Fig 2 13A Operating Instructions T ype 576 e z 3 opea o lt N A2OI Y m 2 PR Yr Mrs tte tl if oma Fig 2 13 A Ic vs Vcg for 10 steps of base current at 50 LA per step B Ic vs VBE for 10 steps of lease current at 50 JA per step 53 Set the HORIZONTAL switch to 1 V BASE Note the display of the collector current vs base emitter voltage for ten different values of
11. from nominal peak open circuit collector voltages and nominal series resistance values at nominal line voltage When MAX PEAK VOLTS switch is set to either 75 350 or 1500 a pro tective box must be in place over test terminals and its lid closed be Safety Interlock 1 1 Specification T ype 576 fore voltage can be applied Amber light on indicates interlock is open Red light on indicates voltage is be ing applied to test terminals Looping Compensation Cancels stray capacitance between collector test terminal and ground in Standard Test Fixture and all Standard Test Fixture Accessories Step Generator Accuracy Current or Voltage Steps Includ ing Offset Incremental Within 5 between any two steps Accuracy without 1X STEP MULT button pressed within 10 with 1X STEP MULT button pressed Absolute Within 296 of total output includ Accuracy ing any amount of offset or 196 of AMPLITUDE switch setting which ever is greater Step Current or One times or O 1 times with 1X Voltage Amplitudes STEP MULT button pressed the AMPLITUDE switch setting OFFSET MULT Con Continuously variable from O to 10 trol Range times AMPLITUDE switch setting either aiding or opposing the step generator polarity Current Mode AMPLITUDE Switch Range 200 mA to 50 nA in 1 2 5 se quence Maximum Current 20 times AMPLITUDE switch set Steps and Aiding ting except 10 times switch setting Of
12. ground Step Generator polarity is inverted OPEN OR EXT Emitter ter minal of Device Under Test is open External signal applied to EXT BASE OR EMIT INPUT connector wil be applied to emitter terminal STEP GEN Inverted Step Gen erator output is applied to emit ter of Device Under Test LEFT OFF RIGHT Selects which device choice of 2 is to Switch be tested left or right Interlock Enables Collector Supply when Protec Switch tive Box is in place and lid is closed Connectors Adapter Allows connection of various test Connectors adapters to Standard Test Fixture Connectors will accept standard size p banana plugs if some other means of connecting Device Under Test to Standard Test Fixture is desired C B and E stand for collector base and emitter respectively Unlabeled termi nals allow Kelvin sensing of voltage for high current devices STEP GEN OUT Step Generator output signal appears Connector at this connector EXT BASE OR Allows input of externally generated EMIT INPUT signal to either base terminal or emit Connector ter terminal of Device Under Test as determined by Terminal Selector Switch GROUND Provides external access to ground ref Connector erence Light Red light on indicates Collector Sup ply is enabled and dangerous voltage may appear at collector terminals Caution Light Rear Panel Controls Line Voltage Selector Switches switch assembly selects Op Also includes lin
13. is pressed When the 80 us PULSED STEPS button is pressed the duration of the pulsed steps is 80 Us When either the 300 us button or the 80 us button is pressed the Collector Supply mode is auto matically set to DC If the 300 us and 80 us buttons are pressed together the Collector Supply remains in the nor mal mode and 300 us pulsed steps are produced in all the previously mentioned cases the pulses occur at the peak of the Collector Supply sweep and therefore only the normal and 5 times normal Step Generator rates are available for USE Standard Test Fixture The Standard Test Fixture which slides into the front of the Type 576 provides a means of connecting the Collector Supply output the Step Generator output and the display amplifiers to the device to be tested he Terminal Selector switch located on the Standard Test Fixture determines the state of the base and the emit ter terminals of the device under test The switch has two ranges EMITTER GROUNDED and BASE GROUNDED In the EMIT TER GROUNDED range the emitter terminal is connected to ground and the Terminal Selector switch determines the state of the base terminal With the switch set to STEP GEN the Step Generator output is applied to the base terminal In the OPEN OR EXT position the base terminal is left open In this case measurements may be made with the base terminal left open or with an exter nally generated signal applied to it through the EXT BASE
14. section Use of the magnifier is discussed in both the Vertical and Horizontal Measure ment and Deflection Factor sections Collector Supply The Collector Supply provides operating voltage for the device under test It is a variable voltage in the form of either a sine wave or a full wave rectified sine wave see Fig 2 22 This voltage is applied to the collector terminals of the Standard Test Fixture he MAX PEAK VOLTS switch and the VARIABLE COLLECTOR SUPPLY control determine the peak voltage output of the Collector Supply which may be varied from O volts to 1500 volts The MAX PEAK VOLTS switch pro vides four peak voltage ranges 15 volts 75 volts 350 volts and 1500 volts The VARIABLE COLLECTOR SUPPLY allows continuous voltage variation of the peak voltage within each peak voltage range The PEAK POWER WATTS switch which interlocks with the MAX PEAK VOLTS switch determines the maxi mum power output of the Collector Supply Power output The Horizontal display is not calibrated when the VERTICAL switch is set between 100 nA and 1 nA EMITTER A een Operating Instructions Type 576 TABLE 2 4 Measurements Made by the Type 576 Display Switch Settings VERTICAL COLLECTOR COLLECTOR COLLECTOR HORIZONTAL COLLECTOR EMITTER GROUNDED VCE BASE EMITTER GROUNDED VBE Measured by Display Horizontally COLLECTOR COLLECTOR BASE GROUNDED VCB COLLECTOR BASE BASE GROUNDED Veg COLLECTOR EMITTER EMITTE
15. sine 11 ms duration 1 shock per axis Total of 6 shocks Nonoperating 12 inch package drop Qualified un der the National Safe Transit Com mittee test procedure 1A Transportation TABLE 1 3 MECHANICAL CHARACTERISTICS Characteristic Description Dimensions Height 2 15 inches Width 311 3 4 inches Depth 8223 1 4 inches Weight 1 69 Ibs Finish Front Panel Type Anodized Aluminum 576 and Standard Test Fixture Cabinet Blue vinyl painted aluminum Trim and Rear Satin finished chrome Panel This page intentionally blank LE Type 576 SECTION 2 OPERATING INSTRUCTIONS Change information if any affecting this section will be found at the rear of the manual General This section of the instruction manual provides informa tion necessary for operating the Type 576 and for using it to test various semiconductor devices Included are setup procedures a description of the Type 576 controls and connectors a discussion of the theory of the instrument a first time operation procedure and general operating infor mation Also included is a section describing the use of the Type 576 for measuring the characteristics of various semi conductor devices INITIAL CONSIDERATIONS Cooling The Type 576 maintains a safe operating temperature when operated in an ambient temperature of O C 122 F Adequate clearance on all sides of the instrument should be provided to assure free air flow and dissipation of h
16. terminal of the device under test The Step Generator produces ascending steps of current or voltage at a normal rate of one step per cycle of the Collector Supply The amount of current or voltage per step is controlled by the AMPLITUDE switch and the total number of steps is controlled by the NUMBER OF STEPS switch This Step Generator output may be applied to either the base or the emitter or equivalent terminals of the device under test The display amplifiers are connected to the device under test These amplifiers measure the effects of the Collector Supply and of the Step Generator on the device under test amplify the measurements and apply the resulting voltages to the deflection plates of the CRT The sensitivities of these amplifiers are controlled by the VERTICAL CUR RENT DIV switch and the HORIZONTAL VOLTS DIV switch Fig 2 b is a block diagram showing the connection of these circuits to the device under test for a typical measure ment 2 8 FIRST TIME OPERATION When the Type 5 6 is received it is calibrated and should be performing within the specification shown in Sec tion 1 The following procedure allows the operator to be come familiar with the front panel controls and their func tions as well as how they may be used to display transistor or diode characteristics This procedure may also be used as a general check of the instrument s performance For a check of the instrument s operation with respect to the
17. 1 mA position and note that the slope increases Also note that the PER VERT DIV readout changes in accordance with the position of the VERTICAL switch Reset the VERTICAL switch to 1 mA 18 Repeat step 17 using the HORIZONTAL switch within the COLLECTOR range of the switch The change in slope of the trace will be the inverse of what it was for the VERTICAL switch Reset the HORIZONTAL switch to 1 V COLLECTOR 19 Press the ZERO button Note that the diagonal trace reduces to a spot in the lower left corner of the CRT graticule This spot denotes the point of zero deflection of the vertical and horizontal amplifiers Release the ZERO button 20 Press the CAL button Note that the diagonal trace reduces to a spot in the upper right corner of the CRT graticule The position of this spot indicates 10 divisions of deflection both vertically and horizontally Release the CAL button 21 Press the DISPLAY INVERT button and turn the VARIABLE COLLECTOR SUPPLY control counterclock wise Note that the display has been inverted and is now originating from the upper right corner of the CRT grati cule Release the DISPLAY INVERT button 2 10 Fig 2 7 Type 576 Standard Test Fixture with protective box in stalled for safe operation Collector Supply 22 Turn the MAX PEAK VOLTS switch throughout its range Note that when the switch is in the 75 350 and 1500 positions the yellow light comes on 23 While the yellow light is on
18. CTOR POLARITY PNP Note the display of the reverse voltage characteristic of the Zener diode A3 Position the display to the center of the CRT grati cule with the vertical POSITION switch see Fig 2 11A 44 Set the DISPLAY OFFSET Selector switch to HORIZ X10 Press the ZERO button and using the hori zontal FINE POSITION control adjust the spot so that it is on the center vertical line of the CRT graticule This spot position represents the zero offset position Release the ZERO button and set the DISPLAY OFFSET Selector switch to HORIZ X1 45 Turn the CENTERLINE VALUE switch from the O position clockwise until the Zener breakdown portion of the display is within 0 5 divisions of the center vertical line see Fig 2 11B Note the number on the CENTER LINE VALUE switch which appears in the blue window below the word DIV This number multiplied by the PER HORIZ DIV readout value gives the approximate value of the breakdown voltage of this Zener diode For the diode in the example shown in Fig 2 11 the approximate Zener breakdown voltage is 4 divisions times 2 V division 8 volts 46 Set the DISPLAY OFFSET Selector switch to 2 12 HORIZ X10 Note that PER HORIZ DIV readout value has changed to indicate the 10 times multiplication By expand ing the scale a measurement can be made of that part of the characteristic which was not quite offset to the center vertical line of the CRT graticule see Fig 2 11C Th
19. FORMATION CRT The CRT in the Type 576 has a permanently etched internal graticule The graticule is 10 divisions by 12 divi sions each division being 1 cm Illumination of the grati cule is controlled by the GRATICULE ILLUM control Pro tective shields for the CRT and the fiber optic readout dis play are fitted to the bezel The bezel covers the CRT and the fiber optic readout display o remove loosen the se curing screw and pull out on the bottom of the bezel A blue filter has been provided to improve the contrast of the display when the ambient light is intense This filter may be installed or removed by removing the bezel and sliding the filter from between the CRT protective shield and the bezel frame Readout The readout located to the right of the CRT is made up of the fiber optic displays and their titles The fiber optic displays show numbers and units b mA 2 V etc the Operating Instructions Type 576 values of which are a function of front panel control set tings The titles are words printed on the fiber optic display shield attached to the bezel These words indicate the char acteristics of the CRT display to which each fiber optic display is related PER VERT DIV PER STEP etc Iu mination of the titles and the fiber optic diplays is con trolled by the READOUT ILLUM control It should be noted that as the illumination of the readout is reduced the fiber optic display of B or gm per division turns off
20. ILICON CONTROLLED RECTIFIERS SCR Required Type 576 Control Settings Control Required Setting HORIZONTAL COLLECTOR PEAK POWER WATTS Less than maximum power rating of device POLARITY NPN STEPS Pressed when using low gate voltage or current PULSED STEPS Pressed when using high gate voltage or current Terminal Selector EMITTER GROUNDED BASE TERM STEP GEN Anode C Collector Step Supply Generator Cathode E Vertical Turn on Forward Blocking Voltage Holding Current Reverse Blocking Voltage 2 30 B Gate Ig vs VF for different values of VG Some Common Measurements The gate voltage or current at which the device turns on can be measured by applying a specified voltage between the anode and cathode terminals using the VARIABLE COL LECTOR SUPPLY control and applying current or voltage steps in small increments to the gate with the AMPLITUDE switch To measure the forward blocking voltage set the Terminal Selector switch to BASE TERM OPEN or SHORT depending on the specification and turn the VARIABLE COLLECTOR SUPPLY control clockwise until the device switches to its low impedance state The voltage at which switching occurs is the forward blocking voltage Holding current is measured in the same manner as forward blocking voltage Holding current is the minimum current conducted by the device while operating in its low impedance state without turning off The reverse blocking voltage is measure
21. R STEP GEN STEP GEN STEP GEN STEP GEN BASE l Error in voltage must be calculated See Horizontal Measurement in Deflection Factor section VEg indicates a measurement of forward voltage base emitter with the horizontal voltage sensing leads reversed Fig 2 22 Output of Collector Supply for three settings of PO LARITY switch is controlled by placing a resistor selected from the SERIES RESISTORS in series with the Collector Supply output The series resistance limits the amount of current which can be conducted by the Collector Supply In setting the peak power output using the PEAK POWER WATTS switch the proper series resistor is automatically selected If the peak voltage range is changed while the MAX PEAK 8 BASE GROUNDED Ip er VERB IB or VEg VEB VOLTS and the PEAK POWER WATTS switches are inter locked a new series resistor is chosen which will provide the same peak power output The Collector Supply POLARITY switch determines the polarity of the Collector Supply output and the Step Generator output It also provides an initia display position on the CRT graticule as discussed in the section on post tioning When the POLARITY switch is set to NPN the Collector Supply output is a positive going full wave recti fied sine wave and the Step Generator output is positive going When the switch is set to PNP the Collector Sup ply output is a negative going full wave rectified sine wave and the
22. Selector switch setting AMPLITUDE switch setting 1X STEP MULT button position X10 Vertical Interface Input and X10 Step Interface Input Power Requirements Power Connection This instrument is designed for operation from power source with its neutral at or near ground earth potential It is not intended for operation from two phases of multi ohase system or across legs of single phase three wire system It is provided with a three wire power cord with three terminal polarized plug for connection to the power source hird wire is directly connected to instrument frame and is intended to ground the instrument to protect operating personnel as recommended by national and international safety codes Line Voltage Ranges 115 VAC 230 VAC Low 90 V to 110V 180V to 220 V Medium 104 V to 126 V 208 V to 252 V High 112 V to 136 V 224 V to 272 V Line Frequency Range 48 to 66 Hz Maximum Power 305 W 32 A Consumption at 115 VAC 60 Hz Table 1 2 ENVIRONMENTAL CHARACTERISTICS Characteristic Information Temperature Nonoperating 40 C to 65 C Specification T ype 576 Useful Operation O C to 50 C Specified Operation 10 C to 40 C Altitude Nonoperating To 50 000 feet _ Operating To 10 000 feet Vibration Operating 15 minutes along each axis at 0 015 inch with frequency varied from 10 50 10 c s in 11 minute cycles Three minutes at any resonant point or at 50 c s Shock 30 g s 1 2
23. Set the control for desired illumination 5 urn the READOUT ILLUM control throughout its range Note that the fiber optic readouts and the readout titles become illuminated as the control is turned clockwise Set the control for the desired readout illumination The readout should read for these initial control settings 1 mA per vertical division 1 V per horizontal division 50 nA per step and 20 k f or gm per division 6 Turn the INTENSITY control clockwise until a spot appears at the center of the CRT graticule To avoid burn ing the CRT phosphor adjust the INTENSITY control until the spot is easily visible but not overly bright 7 Turn the FOCUS control throughout its range Ad just the FOCUS control for a sharp well defined spot Positioning Controls 8 Turn the vertical FINE POSITION control through Out its range Note that the control has a range of at least 2 5 divisions about the center horizontal line Set the con trol so that the spot is centered vertically on the CRT arati cule 9 Repeat step 8 using the horizontal FINE POSITION control 10 Turn the vertical coarse POSITION switch Note that the spot moves 5 divisions vertically each time the switch is moved one position The extreme positions of the switch represent 10 divisions of deflection which in this case causes the spot to be off the CRT graticule Set the POSITION switch to the center position 10 Turn the vertical coarse POSITION switch N
24. Step Generator output is also negative going The AC position of the POLARITY switch provides a Collector Supply output which is an unrectified sine wave and the Step Generator output is positive going A negative going Step Generator output can be obtained in this case by pressing the STEP OFFSET POLARITY INVERT button As noted on the front panel when the AC position is being used the MODE switch should be set to NORM and the Step Generator rate to 5X The MODE switch determines whether the Collector Supply output voltage will be a voltage sweep or a DC voltage When the MODE switch is set to NORM the output is a repetitive voltage sweep varying from O volts to the 2 21 Operating Instructions T ype 576 peak voltage set by the MAX PEAK VOLTS switch and the VARIABLE COLLECTOR SUPPLY control When the MODE switch is set to DC ANTILOOP or LEAKAGE EMITTER CURRENT the Collector Supply output is a DC voltage equal to the peak voltage set by the MAX PEAK VOLTS switch and the VARIABLE COLLECTOR SUPPLY control This DC voltage may be either positive or negative The DC mode is very useful when the normal display is exhibiting excessive looping Occasionally some of the characteristic curves displayed on the CRT consist of loops rather than well defined lines see Fig 2 23 This effect is known as looping and is most noticeable at very low or very high values or current Looping is generally caused by stray capacitance within the Type
25. UT GROUND Fig 2 25 Control setup chart for the Type 576 front panel 2 on OR EMIT INPUT connector When the Terminal Selector switch is set to BASE TERM SHORT the base terminal is shorted to the emitter In the BASE GROUNDED range the base terminal is connected to ground and the Terminal Selector switch de termines the state of the emitter terminal With the switch set to STEP GEN the Step Generator output is inverted and applied to the emitter terminal When the switch is set to OPEN OR EXT the emitter terminal is left open In this case measurements may be made with the emitter ter minal left open or with an externally generated signal applied to it through the EXT BASE OR EMIT INPUT connector Tektronix Type 576 device testing accessories may be plugged into the 10 Accessories connectors provided on the Standard Test Fixture These accessories provide sockets into which semiconductors with various lead arrangements may be placed for testing The 10 Accessories connectors allow the settina up of two devices at a time for comparison testing The LEFT OFF RIGHT switch determines which device is under test The 10 Accessories connectors also Some of these accessories are made of plastic and are susceptible to damage from excessive heat If a device is likely to heat exces sively a heat sink or the pulsed steps mode of operation should be used Operating Instructions T ype 576 accept standard banana plu
26. ach end and connect it between the STEP GEN OUTPUT connector and the EXT BASE OR EMIT INPUT connector 80 Set the following Type 576 controls to STEP FAMILY ON LEFT OFF RIGHT RIGHT BASE TERM OPEN OR EXT Terminal Selector Note a display similar to that seen in step 78 81 Set the following Type 576 controls to VERTICAL 1 nA EMITTER MODE LEAKAGE VARIABLE COLLEC Fully Counterclockwise TOR SUPPLY STEP FAMILY OFF Remove the patch cord 82 Turn the VARIABLE COLLECTOR SUPPLY con trol clockwise and note the display of emitter leakage cur rent with the base terminal open 83 Set the Terminal Selector switch to SHORT and note the display of emitter leakage current with the base terminal shorted to ground 84 Set the following Type 5 6 controls to VERTICAL 5 mA AMPLITUDE 5 mA Terminal Selector EMITTER TERM STEP GEN STEP FAMILY ON Turn the VARIABLE COLLECTOR SUPPLY control clockwise and note the display of collector current vs collector emitter voltage with current steps applied to the emitter of the transistor see Fig 2 19B 85 Set the following Type 576 controls to STEP FAMILY OFF EMITTER TERM OPEN OR EXT Terminal Selector Reconnect the patch cord between the STEP GEN OUT PUT connector and the EXT BASE OR EMIT INPUT con nector 86 Set the STEP FAMILY button to ON and note a display similar to that seen in step 84 This completes the first time operation GENERAL OPERATING IN
27. appearing in blue window multi plied by 10 represents number of divisions centerline of display is off set either vertically or horizontally from zero offset line Selects the horizontal deflection factor of display COLLECTOR Horizontal display represents collector voltage to ground BASE Horizontal display repre sents base voltage to ground STEP GEN Steps indicating Step Generator output are displayed horizontally AMPLITUDE switch setting per division determines hori ZERO Button CAL Button zontal deflection factor Provides a zero reference for the dis play NORM When DISPLAY OFFSET selector switch is set to NORM OFF ZERO button provides point on CRT of zero vertical and horizontal deflection for adjusting position controls DISPLAY OFFSET When DIS PLAY OFFSET Selector switch is in one of four display offset posi tions ZERO button provides ref erence point on CRT which must be positioned to vertical centerline horizontal offset or to horizontal centerline vertical offset to insure that the CENTERLINE VALUE switch setting applies to centerline Should always be checked with DISPLAY OFFSET Selector switch is set to MAGNIFIER Provides signal which should cause 10 divisions of vertical and horizontal de flection for checking calibration of vertical and horizontal amplifiers NORM When DISPLAY OFFSET selector switch is set to NORM OFF CAL button provides point on CRT of 10 divisions of ve
28. base current see Fig 2 13B 54 Set the VERTICAL switch to STEP GEN and the HORIZONTAL switch to 1 V COLLECTOR Note the dis play of the base current one step per vertical division vs the collector emitter voltage see Fig 2 14A 55 Set the HORIZONTAL switch to 1 V Base Note the display of base current one step per vertical division vs base emitter voltage see Fig 2 14B 56 Set the VERTICAL switch to 5 mA and the HORI ZONTAL switch to STEP GEN Note the display of collec tor current vs base current one step per horizontal division see Fig 2 15 57 Set the following Type 576 controls to HORIZONTAL 1 V COLLECTOR RATE DA Note that the step rate is slower than the normal rate 2 13 Operating Instructions T ype 576 ma ny ap i t i 1 l B g vs VBE Fig 2 14 A Ip vs VCE Ip 50 HA per division B Ip vs VBE Ip amp 50 PA per division Fig 2 15 Ic vs Ip Ig 50 HA per division 58 Press the NORM RATE button and then the 2X RATE button Note that the step rate is faster than the normal rate 59 Press both the 2X RATE and 5X RATE buttons Note that the step rate is normal but that the steps occur 2 14 at the peak of each collector sweep rather than at the beginning of each collector sweep as when the NORM RATE button is pushed 60 Press the SINGLE STEP FAMILY button Press it again Note that each time the SINGLE button is pressed a
29. before the other fiber optic displays Intensity The intensity of the display on the CRT is controlled by the INTENSITY control This control should be adjusted so that the display is easily visible but not overly bright It will probably require readjustment for different displays Partic ular care should be exercised when a spot is being dis played A high intensity spot may burn the CRT phosphor causing permanent damage to the CRT Focus The focus of the CRT display is controlled by the FO CUS control This control should be adjusted for optimum display definition Positioning The position of the display on the CRT graticule both vertically and horizontally is controlled by four sets of controls the vertical and horizontal POSITION controls the POLARITY switch the DISPLAY OFFSET controls and the DISPLAY INVERT ZERO and CAL buttons The position controls provide coarse and fine positioning of the display both vertically and horizontally Each coarse POSITION switch provides 5 division increments of display positioning Each FINE POSITION control has a contin uous range of greater than 5 divisions The position controls should not be used to position the zero reference off the CRT The DISPLAY OFFSET controls may be used for this purpose If the display is magnified either vertically or hor izontally using the DISPLAY OFFSET Selector switch the ranges of the position controls are increased 10 times The POLARITY switc
30. d the same way as the forward blocking voltage except that the POLARITY switch is set to PNP per um SENE NER ES pe S a E poco Hum anm ER EB EM me mE EE Operating Instructions Type 576 SIGNAL DIODES AND RECTIFYING DIODES Required Type 576 Control Settings Control Required Setting HORIZONTAL COLLECTOR PEAK POWER WATIS Less than maximum power rating of device POLARITY i NPN Terminal Selector EMITTER GROUNDED Sms m Collector Supply N 20I m a p a x py puur y 0 09 9 z t k L4 4 Li t i L L 1 j i LI Some Common Measurements IF and VF To measure forward current and voltage put the cathode of the diode in the emitter terminal of the test socket and the anode of the diode in the collector terminal Apply voltage to the device with the VARIABLE COLLECTOR SUPPLY control IR and VR Current and voltage in the reverse direction are measured in the same manner as in the forward direction except that the POLARITY switch is set to PNP For measurements of small amounts of reverse current set the MODE switch to LEAKAGE EMITTER CURRENT ZENER DIODES Required Type 576 Control Settings Control Required Setting HORIZONTAL COLLECTOR PEAK POWER WATTS Less than maximum power rating of device POLARITY PNP Terminal Selector EMITTER GROUNDED A 2 31 Operating Instructions Type 576 Anode C Collector Supply Cathode E emo ree e v r ey FH 9 t t
31. deflection om tre CRT 3 plus 0 125 V for each vertical division of deflection on the CRE 3 plus 0050 y for each vertical division of deflection of the CRT 1 3 Specification Type 576 Vertical Step 3 A 5 A Generator Vertical and Horiz Horizontal Step 396 4 5 496 Generator Deflection Factors Vertical Collector Current Display Offset 1 uA division to 2 A division in 1 2 5 sequence Display Positioning Accuracy Using POLARITY Switch 1 nA division to 2 mA division in 1 2 5 sequence Emitter Current Step Generator 1 step division Horizontal AC Collector Volts 50 mV division to 200 V division NPN in 1 2 5 sequence PNP Base Volts 50 mV division to 2 V division in 1 2 5 sequence CRT Type Input Imped At least 100 MR with HORIZON ance TAL switch set to 50 mV 100 mV Screen Size and 200 mV BASE 1 MQ within 2 with switch set to 5 V 1 V and 2 V Step Generator 1 step division Typical Accel Maximum Displayed lerating Poten tial Noise 1 or less or Readouts MAX PEAK VOLTS Switch Vertical COLLECTOR TUA TUA 2UA 5 LA EMITTER 5nA PER VERT DIV Horizontal COLLECTOR 5mV 5mV 20mV 200mV BASE 5 mV With DISPLAY OFFSET Selector switch set to NORM OFF spot is deflected 10 divisions both vert ically and horizontally within 1 596 whenever the CAL button is pres sed Calibration Check PER HORIZ DIV With DISPLAY OFFSET Selector PER STEPS switch set
32. dout and the switch position should coincide When the MODE switch is set to LEAKAGE EMITTER CURRENT the CRT display measures emitter current ver tically In this case the vertical sensitivity of the display is increased by 1000 times for each position of the VER TICAL switch The vertical deflection factor is indicated either by the PER VERT DIV readout or by the position of the VERTICAL switch using the letters printed in orange to determine units When the MODE switch is set to LEAK AGE the output of the Collector Supply is DC voltage like that obtained when the MODE switch is set to DC ANTI 1 OOP rather than a voltage sweep Also in the leakage mode a slight error up to 1 25 V is added to the horizon tal display The following Horizontal Measurement and De flection Factor section shows how to determine the degree of this error NPN HORIZ CAL PNP HORIZ ZERO AC VERT ZERO NPN VERT ZERO PNP VERT CAL NPN NORM ZERO PNP NORM CAL Operating Instructions T ype 576 ACHORIZCAL Ac NORM CAL X PNP NORM ZERO NPN NORM CAL l NPN VERT CAL PNP VERT ZERO AC HORIZ ZERO NPN HORIZ ZERO PNP HORIZ CAL Fig 2 20 Positions of spot on CRT graticule when ZERO or CAL buttons are pressed for various positions of the POLARITY switch and the DISPLAY OFFSET Selection switch assuming the position controls are centered When the VERTICAL switch is set to STEP GEN steps indicating the Step Generator o
33. e 576 LEAKAGE EMITTER CUR RENT Vertical sensitivity is in creased 1000 times Vertical ampli fier measures emitter current Col lector Supply mode set for DC volt age output Allows adiustment of looping compen sation Allows compensation of inter nal and adapter stray capacitance Does not compensate for device ca pacitance Resets Collector Supply if it has been disabled by internal circuit breaker Collector Supply is turned off when ever maximum current rating of trans former primary of 1 2 Amperes is ex ceeded Controls input power to instrument Lights when power is on Indicates Collector Supply voltage has been disabled Lights when Collector Supply may present a potentially dangerous voltage at its output in such a case use of protective box is required to enable Collector Supply Also lights when high current gen erated by Collector Supply or Step Generator causes instrument to over heat Step Generator Selects number of steps per family of Step Generator output Provides current limit of the Step Gen erator output when voltage steps are being produced Selects amplitude per step of steps and Offset of Step Generator output Amplitudes within black arc represent current steps within yellow arc volt age steps Note caution on front panel when using voltage steps Allows offsetting of Step Generator output using OFFSET MULT control ZERO No offset available AID Allows z
34. e controls are located Care should be exercised when using controls located in this area Fig 2 4 Controls located in light area of Type 576 front panel could cause damage to a device under test if used improperly GENERAL DESCRIPTION OF INSTRUMENT OPERATION The Type 576 is a semiconductor tester which displays and allows measurement of both static and dynamic semi conductor characteristics obtained under simulated opera ting conditions he Collector Supply and the Step Genera tor produces voltages and currents which are applied to the device under test The display amplifiers measure the effects of these applied conditions on the device under test 2 7 Operating Instructions T ype 576 Collector Supply Horizontal Amplifier Step Generator Current Sensing Horizontal Deflection Plates Vertical Amplifier Vertical Deflection Plates Resistor Fig 2 5 Basic Block diagram showing typical connections of Collector Supply Step Generator and Display Amplifiers to the device under test The result is families of characteristics curves traced on a CRT The Collector Supply circuit normally produces a full wave rectified sine wave which may be either positive or negative going The amplitude of the signal can be varied from O to 1500 volts as determined by the MAX PEAK VOLTS switch and the VARIABLE COLLECTOR SUPPLY control This Collector Supply output is applied to the col lector or equivalent
35. e fuses Voltage Selector Selects operating voltage 115 V or 230 V Range Selector Selects line voltage range low medium high Allows conversion of instrument for operation with either 60 Hz or BO Hz line frequency 60 Hz 50 Hz Switch FRONT PANEL COLORS The various colors on the front panel of the Type 576 and Standard Test Fixture indicate relationships between controls and control functions Table 2 2 shows the rela tionship which each color indicates Table 2 2 Colors and Controls Color Relationship Green Indicates controls which affect the Step Generator polarity Blue Indicates controls and statements as sociated with display offset Orange Indicates relationship of LEAKAGE EMITTER CURRENT mode with the VERTICAL and HORIZONTAL switches 8 erating voltage and line voltage range Operating Instructions T ype 576 Indicates controls and statements as sociated with the voltage mode of op eration of the Step Generator Yellow Black Buttons Indicates function controlled by a single button which is released for most common applications Dark Grey Buttons Indicates function controlled by sever al buttons and the dark grey button ts pressed for most common applica tions PRECAUTIONS A number of the Type 5 6 front panel controls could through improper use cause damage to the device under test Fig 2 4 indicates the area of the Type 5 6 front panel where thes
36. eat away from the instrument A thermal cutout in the instrument provides thermal protection by disconnecting the power to the instrument if the internal temperature exceeds a safe operating level Power is automatically restored when the temperature returns to a safe level t should be noted that the instrument will turn off under certain conditions of high collector supply current output or high step generator current output even though the instrument is being operated in an ambient temperature which is within the specified range See footnotes in the Specification section for further information Operating Voltage and Frequency The Type 5 6 can be operated from either a 115 volt or a 230 volt line voltage source The LINE VOLTAGE SE LECTOR assembly located on the rear panel allows con version of the instrument so that it may be operated from one line voltage or the other In addition this assembly changes the connections of the power transformer primary to allow selection of one of three regulating ranges see Table 2 1 The assembly also includes the two line fuses When the instrument is converted from 115 volt to 230 volt operation or vice versa the assembly selects the proper fuse to provide the correct protection for the instrument The Type 576 may be operated from either a 50 Hz or a 60 Hz line frequency In order to synchronize the step generator with the collector supply the 60 Hz 50 Hz switch located on the Type 576 rear
37. ermine vertical deflec tion factor 2 3 Operating Instructions T ype 576 EMITTER Operation of instru ment with MODE switch set to LEAKAGE EMITTER CUR RENT Vertical display represents emitter current Use orange units to determine vertical deflection factor STEP GEN Steps indicating Step Generator output are displayed vertically AMPLITUDE switch set ting per division determines vertical deflection factor DISPLAY OFFSET Allows selection of display offset or Selector Switch CENTERLINE VALUE Switch HORIZONTAL VOLTS DIV Switch 2 4 display offset and maanification NORM OFF Display offset is not operable HORIZ X1 Allows horizontal dis play to be offset using calibrated CENTERLINE VALUE switch VERT X1 Allows vertical display to be offset using calibrated CEN TERLINE VALUE switch HORIZ X10 Horizontal display magnified by 10 times Allows hori zontal display to be offset using calibrated CENTERLINE VALUE switch VERT X10 Vertical display magni fied by 10 times Allows vertical display to be offset using calibrated CENTERLINE VALUE switch Clear plastic flange with numbers on it Provides calibrated offset of dis play X1 VERT or HORIZ Number on CENTERLINE VALUE switch appearing in blue window repre sents number of divisions centerline of display is offset either vertically or horizontally from zero offset line X10 VERT or HORIZ Number on CENTERLINE VALUE switch
38. ero step of Step Gen erator output to be offset as many as 10 steps above its zero offset level 2 b Operating Instructions T ype 576 OFFSET MULT Control STEPS Button PULSED STEPS Buttons STEP FAMILY Buttons RATE Buttons 2 6 OPPOSE Allows zero step of Step Generator output to be offset as many as 10 steps below its zero off set level Provides calibrated offset of step Gen erator output to 10 times AMPLI TUDE setting when either OFFSET AID or OFFSET OPPOSE button is pressed Provides steps of normal duration step lasts for entire period of rate cycle Allows Step Generator output to be applied to Device Under Test for only a portion of normal step duration Pulsed steps occur at peak of Collector Supply output 300 us Selects pulsed steps with duration of 300 us Collector Sup ply is automatically switched to DC mode 80 ps Selects pulsed steps with duration of 80 us Collector Supply is automatically switched to DC mode 300 us and 80 Us When buttons are pressed together selects pulsed steps with duration of 300 Us how ever Collector Supply is not auto matically switched to DC mode Allows steps to be generated in repeti tive families or one family at a time ON REP Provides repetitive Step Generator output OFF SINGLE Provides one family of steps whenever button is pressed Once button has been pressed Step Generator is turned off until pressed again or until ON REP but
39. fset when switch is set to 200 mA and 15 times switch setting when the switch is set to 100 mA Maximum Voltage At least 10 V Steps and Aiding Offset Maximum Opposing Whichever is less 10 times AMPLI Offset Current TUDE switch setting or between 10 mA and 20 mA Maximum Opposing Between 1 V and 3 V Voltage 2 Continuous DC Output vs Time Temperature and Duty Cycle 2A continuous DC output can be achieved for an unlimited period up to 30 C ambient Between 30 C and 40 C ambient 2A continuous DC operation should be limited to 15 minutes or limited to a 50 duty cycle or less A family of steps such as 10 steps at 200 mA per step will automatically reduce the duty cycle to 50 even if genera ted continuously Exceeding the rating will temporarily shut off power to the entire instrument but no damage will result 1 2 0 5 or less of AMPLITUDE switch setting or 4 nA peak to peak Ripple Plus Noise Voltage Mode AMPLITUDE Switch Range 50 mV to 2 V in 1 2 5 sequence Maximum Voltage 20 times AMPLITUDE switch set Steps and Aiding iting Offset Maximum Current At least 2 A at 10 V or less de Steps and Aiding rating linearly to 10 mA at 40 V Offset Short Circuit Cur 20 mA 100 mA 500 mA 100 rent Limiting Steps 095 2 A 50 0 as selected by and Aiding Offset CURRENT LIMIT switch Maximum Opposing 10 times AMPLITUDE switch set Offset Voltage ing Maximum Opposingi Limited be
40. gs so that a device may be con nected to the Type 576 without using a specific device testing accessory The unlabeled Accessories connectors allow Kelvin sensing of voltage under high current conditions Kelvin sensing means that voltage measurements on the collector and the emitter terminals of a device under test are made through separate contacts to the device leads which reduce contact resistance The STEP GEN OUTPUT connector allows the Step Generator output to be used externally The EXT BASE OR EMIT INPUT connector allows application of an ex ternally generated signal to either the base or the emitter of the device under test The external signal is applied to whichever terminal is chosen by the Terminal Selector switch The GROUND connector provides a Type 5 6 ground reference for signals generated or used external in Type 5 6 Polarities of the Collector Supply and Step Genera tor Output Table 2 7 shows the polarities of the Collector Supply and the Step Generator output for various settings of the Collector Supply POLARITY switch and the Terminal Se lector switch TABLE 2 7 Polarities of the Collector Supply and Step Generator Output Switches Collector Supply POLAR ITY AC EMITTER GROUNDED Positive and Negative going AC BASE GROUNDED 1 May be inverted by pressing the POLARITY INVERT button A Polarities Step Generator Negative going Positive going Positive going Negative going Positive go
41. h has been included as a standard accessory with the Type 576 BIPOLAR TRANSISTORS Required Type 576 Control Settings Control HORIZONTAL POLARITY PEAK POWER WATTS AMPLITUDE STEPS PULSED STEPS Terminal Selector OFFSET Required Setting COLLECTOR NPN or PNP depending on the transistor type Less than maximum power rating of device Current steps Pressed when using low base current Pressed when using high base current EMITTER GROUNDED BASE TERM STEP GEN for common emitter family BASE GROUNDED EMITTER TERM STEP GEN for common base family AID pressed if more than 10 steps are desired Common Emitter Family Collector Supply Vertical 2 26 Saame 2 m xs ynv eww INNORARI N DOI 2 UE TT NIN EE E G ET Eu me Ed fed a Eo EE p eee umm E OMEN DERE REOR Rn REPOS a NECEM rn Mec owed ames Ga Ge Get cee ee ei EIE ee ae ea Ic vs Vcg for different values of Ip i L k t Li Li Li b i Li dpe B Static p Small Signal VCE Sat IC vs VBE ICEO and BVCEO IcES and BVcES ICER and BVCER Operating Instructions Type 576 Some Common Measurements The static forward current transfer ratio emitter grounded hFE is IC lB The small signal short circuit forward current transfer ratio emitter grounded hfe IS lc Alg To determine hfe at various points in a family of curves multiply the vert
42. h positions the zero signal point of a display located by pressing the ZERO button to a posi tion convenient for making measurements on an NPN de vice a PNP device or when making an AC measurement The DISPLAY OFFSET controls provide calibrated off set or positioning of the display either vertically or hori zontally These controls may be used either to make a measurement or to position particular portions of a display which has been magnified on the CRT graticule he DIS PLAY OFFSET Selector switch determines whether the dis play will be offset vertically or horizontally and the CEN TERLINE VALUE switch provides the offset Under un magnified conditions 10 divisions of offset are available When the DISPLAY OFFSET Selector switch is set to one of its MAGNIFIER positions 100 divisions of offset are available 2 17 Operating Instructions T ype 576 When making a measurement using the DISPLAY OFF SET controls the CRT graticule becomes a window When the CENTERLINE VALUE switch is set to O the vertical centerline horizontal offset or the horizontal centerline vertical offset of the window is at the zero signal portion of the display As the CENTERLINE VALUE switch is turned counterclockwise the window moves either ver tically or horizontally along the display For each position of the CENTERLINE VALUE switch the number on the switch appearing in the blue window represents the number of divisions the vertical cente
43. ical separation of two adjacent curves by the 8 OR gm PER DIV readout To make a more accurate measurement see steps 69 through 74 of the First Time Operation instructions Saturation current and voltage is measured by expanding the display of the saturation region of the device by decreasing the horizontal deflection factor with the HORIZON TAL switch or the DISPLAY OFFSET MAGNIFIER Saturation current can be adjusted to the desired operating point with the AMPLITUDE switch Base emitter voltage can be measured by setting the HORIZONTAL switch to the BASE range Collector emitter leakage current and collector emitter breakdown voltage base open are measured by setting the Terminal Selector switch to BASE TERM OPEN OR EXT For small leakage currents set the MODE switch to LEAKAGE EMITTER CURRENT To measure breakdown voltage increase both the horizontal deflection factor and the collec tor supply voltage Collector emitter leakage current and collector emitter breakdown voltage base shorted to emitter are measured the same as ICEQ and BVCEQ except that the Terminal Selector switch is set to BASE TERM SHORT Collector emitter leakage current and collector emitter breakdown voltage with a speci fied resistance between the base terminal and the emitter terminal are measured the same as ICEQ and BVCEO except that a specified resistance is connected between the base terminal and the emitter terminal Common Base Family Collector
44. in source voltage with voltage steps of 0 05 V step fi Va T PG mnt L 1 1 t 1 T 1 i A oo o o es d am am amp A a o E a N E WA Wy d LE 4 pae NW NNNM E Fig 2 17 Display of FET common source characteristic curves Ip vs Vps for 10 steps of gate voltage at 0 05 volts step applied to the gate see Fig 2 17 Since the steps applied to the gate are positive going the curves displayed represent enhancement mode operation of the FET Press the SINGLE STEP FAMILY button to locate the curve obtained with zero volts on the gate 67 Press the POLARI TY INVERT button and note the display of the depletion mode of operation of the FET see Fig 2 17 Press SINGLE STEP FAMILY button for zero bias curve 68 Set the Type 576 LEFT OFF RIGHT switch to OFF Remove the universal FET test adapter and replace it with the universal transistor test adapter with the transistor stil in it 69 Set the following Type 576 controls to A Operating Instructions T ype 576 VERTICAL 5 mA AMPLITUDE Current Steps NUMBER OF STEPS 5 POLARITY INVERT Released set the AMPLITUDE switch and the VARIABLE COLLECTOR SUPPLY control for a family of curves similar to Fig 2 18A 70 Note the B or gm per division readout By measuring the vertical divisions between two curves of the displayed family the B of the device in that region can be determined For exa
45. ing Positive and Negative going Negative going 2 25 Operating Instructions T ype 576 APPLICATIONS This part of the Operating Instructions describes the use of the Type 576 to measure some basic parameters of bi polar transistors field effect transistors unijunction transis tors silicon controlled rectifiers signal and rectifier diodes Zener diodes and tunnel and back diodes For each of the devices discussed this section includes tables of Type 576 contro settings required to make an accurate measurement without damaging the device under test Below each table is a block diagram showing the connections of the collector supply the step generator and the display amplifiers to the device under test and a picture of a typical characteristic for the semiconductor type being discussed Also included is a list of common measurements which may be made on the given devices with the Type 576 and a brief set of instructions on how to make each of these measurements This section has been written with the assumption that the reader is familiar with the operation of the Type 576 as described at the beginning of the Operating Instructions It Is also assumed that the reader is familiar with the para meters being discussed f an explanation or further infor mation about semiconductor parameters and their measure ment is needed refer to the Tektronix Measurement Con cepts book titled SEMICONDUCTOR DEVICE MEASURE MENTS whic
46. is value when added to the approximate value or subratcted wal IT Display Offset A 2n ODivisions Seas SRR nea sca eee Rane ee eRe 9 o x z N A2OI 3 e nm 9 t5 mao ou M lt 33 PER v E R Li DIM PEN H o R Z Div ETE amma A EE ida nore A a 4 BEBE A E jo ERRowsem M LII NAN LLL LE LI ULLA ENSNMEZSEEERS NA a 9 LE E pos presas a o SR umm ogo 2 maap oe me mee ee eee 1 23 Fig 2 11 Displays of measurement of Zener breakdown voltage using the DISPLAY OFFSET Selector and CENTERLINE VALUE switches A DISPLAY OFFSET Selector switch set to HORIZ X1 and CENTERLINE VALUE switch set to 0 B CENTERLINE VALUE switch set to 4 C DISPLAY OFFSET Selector switch set to HORIZ X10 if the approximate value was greater than the actual value produces a more exact measurement of the breakdown volt age In the example shown in Fig 2 11 400 mV should be 1 4 i N f T added to the approximate estimate yielding a value of 8 4 for the Zener voltage of the diode The same process can also be carried out using vertical display offset and magnifi cation Step Generator 47 Set the following Type 576 controls to DISPLAY OFFSET NORM OFF Selector CENTERLINE VALUE Vertical POSITION Switch centered POLARITY NPN VARIABLE COLLEC Fully Counterclockwise TOR SUPPLY LEFT OFF RIGHT OFF 48 Remove the
47. lay are Vcg and Vcg To make these meas urements the HORIZONTAL switch is set within the COLLECTOR range and the Terminal Selector switch is set to EMITTER GROUNDED or BASE GROUNDED With the VERTICAL switch set between 500 nA division and 1 nA division an error occurs in the horizontal measurement Table 2 3 indicates the degree of this error in voltage per division of vertical deflection for all the settings of the VERTICAL switch within this given range Using this table and the following procedure the actual VCE or VCB can be caluclated TABLE 2 3 Error in Horizontal Voltage Measurement Per Division of Vertical Deflection VERTICAL Switch Setting Voltage Error Per Vertical Division DO nA 5nA 12b mV 20 nA 2 nA 50 mV 100 nA 10 nA 1 nA 25 mV EMITTER current DISPLAY OFFSET Selector switch set to NORM OFF 1 Measure the vertical deflection of the display in divi sions see Fig 2 21 2 Measure the horizontal deflection of the display in volts 3 Using fable 2 3 find the error factor for the setting of the VERTICAL switch and multiply it by the value de termined in step 1 EN E A 3 Divisions WE VAT TT IMA AA Eq p La 325 mV ee A aaa BH t 1 1 4 Voltage error 3 divisions X 25 mV 75 mV Vcg 325 mV 75 mV 250 mV Fig 2 21 Sample calculation of error in collector to emitter voltage incurred when measuring leakage of a transistor 2 20 4 Subtract the voltage deter
48. mined in step 3 from the voltage determined in step 2 to give the actual VCE or VCB When the HORIZONTAL switch is set to STEP GEN steps indicating the Step Generator output are displayed horizontally The horizontal display shows one step per di vision and the amplitude of each step as shown by the PER STEP readout determines the horizontal deflection factor The horizontal deflection factor can be increased by 10 times for any of the previously mentioned measurements by setting the DISPLAY OFFSET Selector switch to HORIZ X10 The magnified horizontal deflection can be determined either from the PER HORIZ DIV readout or by dividing the setting of the HORIZONTAL switch by 10 Measurements Table 2 4 shows the measurements which are being made vertically and horizontally by the display for the various positions of the VERTICAL switch the HORIZONTAL switch and the Terminal Selector switch Those switch posi tion combinations not covered by the table are not con sidered useful Display Offset and Magnifier he DISPLAY OFFSET Selector switch and the CENTERLINE VALUE switch provides a calibrated display offset of from O to 10 divisions O to 100 divisions when the display is magnified and a 10 times display magnifier The display offset and the display magnifier when in opera tion effect the display either vertically or horizontally but never the whole display Use of the calibrate display offset is discussed in the Positioning
49. mple there is approximately 0 9 division between the fourth and fifth steps shown in Fig 2 18A The f of the device when operated in this region is therefore approx imately 0 9 200 or 180 To make a more accurate measurement of f the difference in both collector and base current between the fourth and fifth steps should be less 71 Press the OFFSET AID button and set the OFFSET MULT control to 4 Note that the offset current has been added to the Step Generator output so that the zero step is now at the level of the fourth step displayed 72 Press the STEP MULT 1X button Note that the current per step is now 1 10 of the value set by the AMPLI TUDE switch Check the PER STEP readout for the new amplitude per step See Fig 2 18B 73 Set the DISPLAY OFFSET Selector switch to VERT X1 and turn the CENTERLINE VALUE switch clockwise until the first step is within 0 5 division of the center horizontal line 4 Set the DISPLAY OFFSET Selector switch to VERT X10 Note that though the 8 per division is still 200 as it was in step 70 the change in collector and base current Ic and Alp is less between the fourth and the fifth step This allows for a more accurate measurement of f at the level of the fourth step see Fig 2 18C The B of the device at the fourth step now measures at about 0 8 200 160 75 Set the following Type 576 controls to VERTICAL 1 mA DISPLAY OFFSET NORM OFF Selector AMPLITUDE 05 V NUMBER OF
50. ng on the positions of the POLARITY switch and the DISPLAY OFFSET Selector switch Fig 2 20 shows these positions of the spot for the various settings of the two switches To determine the spot positions when the INVERT button is pressed assume the graticule shown is inverted both vertically and horizontally Vertical Measurement and Deflection Factor In the vertical dimension the display on the CRT meas ures either collector current lc emitter current IE or the output of the Step Generator The MODE switch and the VERTICAL switch determine which of these measure ments are made The Vertical deflection factor of the display on the CRT is controlled by the VERTICAL switch the DISPLAY OFFSET Selector switch and the MODE switch The PER VERT DIV readout to the right of the CRT indicates the vertical deflection factor due to the combined effects of these three controls Under normal operating conditions with the MODE switch set to NORM and the DISPLAY OFFSET Selector switch set to NORM OFF collector current is measured vertically and the VERTICAL switch determines the verti cal sensitivity of the display When measuring collector current the VERTICAL switch provides deflection factors unmagnified ranging from 1 uL A division to 2 A division The vertical deflection factor is indicated either by the PER VERT DIV readout or by the position of the VERTICAL switch using the letters printed in black to determine units The rea
51. oltage steps which may be applied to either the base terminal or the emitter terminal of the device under test Step generator outputs range from 5 nA to 2 A in the current mode and from 5 mV to 40 V in the voltage mode The steps may also be produced as short duration pulses Calibrated step offset allows offsetting the step generator output either positive or negative The vertical display amplifier measures either collector current or leakage current with a maximum deflection factor of 1 nA division when making a leakage TABLE 1 1 ELECTRICAL CHARACTERISTICS Collector Supply Characteristic Performance Sweep Modes Normal mode AC at line fre quency positive or negative going full wave rectified AC DC mode positive or negative DC No load 296 or less of voltage or 0 1 or less of full range voltage DC Mode Ripple Voltages Accuracy Peak open circuit voltages on all ranges within 43596 and 5 Ranges 15V 75V 350V 1500V l Collector Supply Maximum Continuous Peak Current Operating Time vs Duty Cycle and Ambient Temperature With the PEAK POWER WATTS at 50 only the following limitations apply Maxi mum continuous operating time at rated current 10096 duty cycle into a short circuit is 20 minutes at 25 C ambient or 10 minutes at 40 C ambient Alternatively dury cycle may be limited to 50 at 25 C ambient or 25 at 40 C ambient A normal family of curves for a transistor will produce a duty cycle effect to 50
52. or less even if operated continuously Over dissipation of the collector supply will temporarily shut it off and turn on the yellow COLLECTOR SUPPLY VOLTAGE DISABLED light No damage will result measurement The horizontal display amplifier allows meas urement of both collector and base voltage The following electrical and environmental characteris tics are valid for instruments operated at an ambient tem perature of from 10 C to 40 C after an initial warmup period of 5 minutes when previously calibrated at a tem perature of 25 C 5 C Section 5 Performance Check and Calibration Procedure gives a procedure for checking and adjusting the Type 576 with respect to the following specification The Type 576 MOD 301W is a standard Type 576 with out the Readout Assembly All the information contained in this manual pertaining to the Readout Assembly and its operation should be disregarded when used in conjunction with a modified instrument Maximum Peak 10A ZA 05A 01A Current Normal Mode Peak Current Step At least At least At least At least Generator in Pulsed 20 A 4A 1A 0 2A Steps Mode Minimum Series O32 6582 1402 3k98 Resistance Maximum Series 65bk 2 1 4MQ 65M2 65MQ9 Resistance Series Resistance 0 3 Q 1 4 2 6 5 2 30 QR 140 2 Available 650 2 3 kQ 14 kR 65 kR 300 kR 1 4 MQ and 6 5 M amp all within 596 or 0 1 82 Peak Power Watts 10 1 W 0 5 W 2 2 W 10 W 5OW Settings and 220 W Derived
53. ote that the spot moves 5 divisions vertically each time the switch is moved one position The most extreme positions of the switch represent 10 divisions of deflection which in this case causes the spot to be off the CRT araticule Set the POSITION switch to the center position 11 Repeat step 10 using the horizontal coarse POSI TION switch 12 Set the POLARITY switch to PNP Note that the spot moves to the upper right corner of the CRT arati cule 13 Set the POLARITY switch to NPN Note that the spot moves to the lower left corner of the CRT grati cule Vertical and Horizontal Sensitivity 14 Install the diode adapter Tektronix Part No 2 9 Operating Instructions T ype 576 1 V Div Horizontal ft fA AS 1 mA Div Vertical EMNSS o N AXOIS x m D Ans O voo m bo lt 237 Fig 2 6 Display of I vs V for a 1 kS2 resistor using various settings of the VERTICAL and HORIZONTAL switches 013 0072 00 into the right hand set of accessory connec tors located on the Standard Test Fixture 15 Install a 1 kQ 1 2 watt resistor in the diode adap ter 16 Set the LEFT OFF RIGHT switch to RIGHT and turn the VARIABLE COLLECTOR SUPPLY control until a trace appears diagonally across the CRT 17 Turn the VERTICAL switch clockwise and note that as the vertical deflection factor decreases the slope of the line decreases see Fig 2 6 Turn the VERTICAL switch counterclockwise from the
54. p amp Small Signal Generator Ic vs VcB for different values of lg Some Common Measurements The small signal short circuit forward current transfer ratio base grounded hih can be measured from the common base family display but is determined most easily by calcu lating it from the equation Ok 6 1 B 2 27 Operating Instructions T ype 576 ICBO and BVCBO IEBO and BVEBO Collector Supply gm Small Signal 2 28 Collector base leakage current and collector base breakdown voltage emitter open is measured the same as ICEQ and BVCEO except that the Terminal Selector switch is set to EMITTER TERM OPEN OR EXT Emitter base leakage current and emitter base breakdown voltage collector open is measured the same as Icgo and BVCRO except that the device terminals are inverted in the device testing socket collector lead in the emitter terminal of the socket and the emitter lead in the collector terminal FIELD EFFECT TRANSISTORS Required Type 576 Control Settings Control Required Setting HORIZONTAL COLLECTOR POLARITY NPN for N channel device PNP for P channel device PEAK POWER WATTS Less than maximum power rating of device AMPLITUDE Voltage Steps STEPS Pressed Terminal Selector EMITTER GROUNDED BASE TERM STEP GEN POLARITY INVE Depletion RT Pressed OFFSET with POLARITY OPPOSE ZERO or AID ressed INVERT button p Drain C Common Source Family m 3 m
55. panel below the LINE VOLTAGE SELECTOR assembly must be set to the posi tion which corresponds to the line frequency being used Use the following procedure to convert this instrument between line voltages regulating ranges or line frequencies 1 Disconnect the instrument from the power source TABLE 2 1 Regulating Ranges Regulating Range Range Selector 115 Volts 230 Volts Switch Position Nominal Nominal _ LO switch bar in 180 to 220 volts 90 to 110 volts 104 to 126 volts 112 to 136 volts left holes M switch bar in middle holes HI switch bar in right holes 208 to 252 volts 224 to 272 volts Range Selector 15 Volt Line 60 Hz 50 Hz Switch 230 Volt Lin Fuse Bottom Fig 2 1 Line Voltage Selector assembly and 60 Hz 50 Hz switch on the rear panel shown with cover removed 2 1 Operating Instructions T ype 576 CRT and Readout TYPE 576 CURVE TRACER TERFRONER INC g POLANA REUS HSA oi via Display Sensitivity and Switching gata tea ld p Uer 5 Step Generator Collector Supply Terminal Selector Switch in gp xe eee adie ne Standard Test Fixture Fig 2 2 Front panel controls connectors and readout 2 Loosen the two captive screws which hold the cover onto the voltage selector assembly then pull to remove the cover 3 To convert from 115 volt to 230 volt line voltage or vice versa pull o
56. parent switch flange appearing above white MAX PEAK VOLTS indicator SERIES RESISTORS are indicated by black indicator PEAK POWER WATTS switch must be pulled out to set nominal peak power output When PEAK POWER WATTS switch is set series resistance is automatically changed to maintain desired nominal peak power output when MAX PEAK VOLTS switch setting is changed Allows varying of collector supply voltage within range set by MAX PEAK VOLTS switch POLARITY Switch Selects polarity of Collector Supply MODE Switch voltage and Step Generator output PNP Collector Supply voltage and Step Generator output are negative going NPN Collector Supply voltage and Step Generator output are positive going AC Collector Supply voltage is both positive and negative going sine wave Step Generator output is positive going When switch is set to AC position use DX step rate and normal mode of operation Selects mode of operation of Collector Supply NORM Normal Collector Supply output is obtained DC ANTILOOP Collector Sup ply output is DC voltage equal to peak value set by VARIABLE COL LECTOR SUPPLY control LOOPING COMPENSATION Control COLLECTOR SUPPLY RESET Button POWER ON OFF Switch Lights POWER Light COLLECTOR SUPPLY VOLT AGE DISABLED Light Controls NUMBER OF STEPS Switch CURRENT LIMIT Switch STEP OFFSET AMPLITUDE Switch OFFSET Buttons Operating Instructions T yp
57. rating voltage steps to test field effect transistors When current steps are being generated the maximum opposing voltage is limited to approximately 2 volts This voltage limiting protects the base emitter junction of a bi polar transistor from reverse breakdown The STEP OFFSET POLARITY INVERT button allows the Step Generator output both steps and offset to be inverted from the polarity at which it was set by the POLA RITY switch It has no effect when the Terminal Selector switch is set to BASE GROUNDED Caution should be exercised when using this button to cause reverse current to flow between the base and emitter terminals Voltage limit A Operating Instructions T ype 576 TABLE 2 5 Polarity of Offset for Polarity of Step Generator Output Step OFFSET Offset Generator Buttons Polarity Current Voltage Positive AID Positive Positive going Positive OPPOSE Negative Negative going Negative AID Negative Negative going Negative OPPOSE Positive Positive going ing occurs when current steps are being generated only when the OPPOSE OFFSET button is pressed When one of the PULSED STEPS buttons is pressed steps are generated in pulses having durations of either 300 us or 80 us offset is unaffected Pulsed operation is use ful when testing a device at power levels which might dam age the device if applied for a sustained length of time Pulsed steps of a 300 us duration occur when the 300us PULSED STEPS button
58. rline or the horizontal center line has been offset from the zero offset line If the display has been magnified the number in the blue window must be multiplied by 10 The ZERO button provides a convenient means of posi tioning the zero reference point on the CRT araticule Un der normal operating conditions DISPLAY OFFSET Selec tor switch set to NORM when the ZERO button is pressed a zero reference spot appears on the CRT graticule This spot indicates the point on the CRT where zero signal is being measured by the vertical and horizontal display amplifiers With the button pressed the positioning con trols may be used to position the spot to a point on the CRT graticule which makes measurements convenient If the DISPLAY OFFSET Selector switch is set to VERT or HORIZ the zero reference point indicates the horizontal or vertical graticule line respectively to which the CENTER LINE VALUE switch setting applies o assure the accu racy of the CENTERLINE VALUE switch settings the zero reference spot should be adjusted using the positioning controls to the appropriate centerline for the offset being used For maximum accuracy of measurement the position of this zero reference point should be adjusted with the DISPLAY OFFSET Selector switch in one of its MAGNI FIER positions The CAL button provides a means of checking the cali bration of the display amplifiers Under normal operating conditions DISPLAY OFFSET Selector s
59. rtical and horizontal deflection DISPLAY OFFSET When DIS PLAY OFFSET Selector switch is in one of four display offset posi tions CAL button provides signal which should cause reference point on CRT to appear on vertical cen terline horizontal offset or on horizontal centerline vertical off set assuming zero reference point was properly adjusted Check should be performed with DIS PLAY OFFSET Selector switch set to MAGNIFIER DISPLAY INVERT Inverts display vertically and horizon Button POSITION Switch Horizontal FINE POSITION Control Horizontal POSITION Switch Vertical tally about center of CRT Provides coarse positioning of horizon tal display Provides fine positioning of horizontal display Provides fine positioning of vertical display FINE POSITION Control Vertical Controls MAX PEAK VOLTS Switch PEAK POWER WATTS Switch VARIABLE COL LECTOR SUPPLY Control Provides fine positioning of vertical display Collector Supply Selects range of VARIABLE COLLEC TOR SUPPLY control Switch is loca ted below PEAK POWER WATTS switch and range is indicated by white arrow When switch is set to 75 350 and 1500 protective box must be used with Standard Test Fixtures see sec tion on interlock system Selects nominal peak power output of Collector Supply by selecting resist ance in series with Collector Supply output PEAK POWER WATTS is indicated by number on trans
60. s repetitive families of steps When the SINGLE STEP FAMILY button is pushed one step family is generated and the Step Generator turns off To get another step family the SINGLE button must be pressed again The OFFSET buttons and the OFFSET MULT control allow current or voltage to be either added or subtracted from the Step Generator output This causes the level at which the steps begin to be shifted either in the direction of the ascending steps aiding offset or in the opposite direction of the steps opposing offset When the ZERO OFFSET button is pushed the step family is generated at its nomal level where the zero step level is either O mA or O V and the OFFSET MULT control is inhibited When the AID OFFSET button is pressed current or voltage may be added to the Step Generator output using the STEP MULT control The amount of current or voltage added to the Step Generator output when the AID button is pressed is equal to the setting of the STEP MULT control times the setting of the AMPLITUDE switch The STEP MULT con trol has a continuous range of 0 to 10 times the setting of the AMPLITUDE switch Pressing the OPPOSE OFFSET button allows either current or voltage to be subrtracted from the Step Generator output the amount subtracted determined by the STEP MULT control Table 2 5 shows the polarity of the offset current or voltage for the two polarities of the Step Generator output Opposing offset is most useful when gene
61. s the horizontal deflection factor due to the combined effects of these two controls Under normal operating conditions with collector cur rent being measured vertically the Terminal Selector switch set to EMITTER GROUNDED and thc DISPLAY OFFSET Selector switch set to NORM OFF the display will meas ure VCE or VBE horizontally To measure Vcg the HORI ZONTAL switch must be set within the COLLECTOR range which has deflection factors between 50 mV division and 200 V division To measure VE the HORIZONTAL switch must be set within BASE range which has deflection factors between PO mV division and 2 V division In both cases the horizontal deflection factors are indicated by both the PER HORIZ DIV readout and the position of the HORIZONTAL switch The two values should coincide When the Terminal Selector switch is set to BASE GROUNDED the horizontal display measures collector to base voltage Vcg with the HORIZONTAL switch in the COLLECTOR range or emitter to base voltage VERB with the HORIZONTAL switch in the BASE range It should be noted that VEB in this case does not indicate a measure ment of the emitter base voltage under a reverse biased con dition It is a measurement of the forward biased base emitter voltage with the horizontal sensing leads reversed 2 19 Operating Instructions T ype 576 When emitter current is being measured by the vertical display the only significant measurements made by the horizontal disp
62. single family of characteristic curves is displayed and then the Step Generator turns off 61 Set the following Type 576 controls to STEP FAMILY REP ON RATE NORM PULSED STERS 300 us Note that the collector supply is in the DC mode and that each step is in the form of a pulse See Fig 2 16A Readjustment of the INTENSITY control may be neces sary 62 Press the 80 us button Note that the duration of each pulsed step is reduced 63 Press both the 300 us and the 80 us buttons Note that the Collector Supply is in the normal mode and the steps are occurring at the peak of the collector sweep with a duration as observed in step 61 see Fig 2 16B eL LLLLLLIe9 EC a E ke NW H Fig 2 16 300 us PULSED STEPS A DC mode B Normal mode 4 64 Set the Type 576 LEFT OFF RIGHT switch to OFF and remove the universal transistor adapter from the Standard Test Fixture Leave the transistor in the adapter Install the universal FET adapter Tektronix Part No 013 0099 00 on the Standard Test Fixture and place an N channel junction FET into the right test socket of the adapter 65 Set the following Type 576 controls to INTENSITY Visible Display VERTICAL 1 mA VARIABLE COLLECTOR Fully Counterclockwise SUPPLY AMPLITUDE 05 V STEPS Pressed 66 Set the LEFT OFF RIGHT switch to RIGHT and turn the VARIABLE COLLECTOR SUPPLY control slowly clockwise Note the display of drain current vs dra
63. source terminal Set the Terminal Selector switch to BASE TERM SHORT and reverse the collector supply polarity This measure ment should not be made on an insulated gate device UNIJUNCTION TRANSISTORS Required Type 576 Control Settings Control Required Setting HORIZONTAL COLLECTOR POLARITY NPN PEAK POWER WATTS Less than maximum power rating of device AMPLITUDE Voltage OFFSET AID STEP FAMILY OFF SINGLE Terminal Selector BASE TERM STEP GEN Emitter C Collector Supply lg vs VEB4 For specified Vg VB Some Common Measurements n The intrinsic standoff ratio is Vp VEB4 VB5VB4 In measuring N Vgg pg S deter mined by the OFFSET MULT control and the AMPLITUDE switch VB5B4 may be measured by setting the HORIZONTAL switch to the BASE range Vp is determined by applying voltage between the emitter and the base terminals using the VARIABLE COLLECTOR SUPPLY control Vp is the voltage at which the emitter base4 junction becomes forward biased VEB the turn on voltage of the emitter base4 junction is determined by setting the Terminal Selector switch to BASE TERM OPEN e 2 29 Operating Instructions Type 576 RBoBy The interbase resistance can be measured by placing the bases lead in the collector terminal of the test socket and the base lead in the emitter terminal Leave the emitter lead at the device open and apply voltage across the two bases with the VARIABLE COLLECTOR SUPPLY control S
64. t l l 1 i V 1 t i 4 t A l t 1 1 1 t 1 1 um oe We mies Im deem cum ae em iem ui dicus escas RACE ng od Some Common Measurements Vz and IR To measure Zener voltage or reverse current put the cathode of the diode in the emitter terminal of the test socket and the anode of the diode in the collector terminal Apply voltage to the device with the VARIABLE COLLECTOR SUPPLY control For a more accurate measurement of Zener voltage see steps 42 through 46 of the First Time Operation instructions For measurements of small amounts of reverse current set the MODE switch to LEAKAGE EMITTER CURRENT Ir and VF Current and voltage in the forward direction are measured in the same manner as in the reverse direction except that the POLARITY switch is set to NPN For a display of currents and voltages in both directions set the POLARITY switch to AC TUNNEL DIODES AND BACK DIODES Required T ype 576 Control Settings Control Required Setting HORIZONTAL COLLECTOR PEAK POWER WATTS Less than maximum power rating of device POLARITY NPN Terminal Selector EMITTER GROUNDED Anode C Collector Supply Cathode E Rs Vertical Display Amp pom o o cm om mo domo per oy mom o woo m t 1 t i 4 i t 4 t 1 E Edd E EA Sr i 2 32 E T IF and VF IR and VR Operating Instructions Type 576 Some Common Measurements To measure the forward current and
65. tch to 75 Note that the maximum peak power value remains at 220 and that the SERIES RESISTORS values change 31 Set the following Type 576 controls to MAX PEAK VOLTS 15 PEAK POWER WATTS 0 1 LEFT OFF RIGHT OFF 32 Remove the resistor from the diode adapter and re place it with a silicon diode Align the diode so that its cathode is connected to the emitter terminal 33 Set the LEFT OFF RIGHT switch to RIGHT and turn the VARIABLE COLLECTOR SUPPLY control clock wise Note the display of the forward voltage characteristic of the diode see Fig 2 8 34 Set the COLLECTOR SUPPLY POLARITY switch to PNP Note the display of the reverse voltage charac teristic of the diode see Fig 2 8 A2m m_m A ewe d doa d a c m a lt o N 20r Jur cat ditai c T t t 4 r t i k Fig 28 Display of forward and reverse bias characteristics of a signal diode Operating Instructions T ype 576 35 Set the following Type 576 controls to POLARITY NPN MODE DC Note that the display of the forward voltage diode char acteristic has become a spot The spot indicates the current conducted by the diode and the voltage across it 36 Turn the VARIABLE COLLECTOR SUPPLY con trol counterclockwise Note that the spot traces out the diode characteristic 37 Set the following Type 576 controls to VERTICAL 1 LA HORIZONTAL 2 V COLLECTOR Vertical POSITION Display
66. to X10 MAGNIFIER either axis the calibration spot is within 0 5 of zero spot previous ly set to CRT graticule center when CAL button is pressed Coarse positioning in b division in ontal Position Control crements within 0 1 division con tinuous fine positioning over at least b divisions for each coarse pos ition Vertical or Horizontal offset of dis play centerline value up to 10 divis ions in 21 half division steps opot positioning with change in POLARITY switch setting using AC position as reference within 0 1 division of Vertically Horizontally Centered 5 division 5 divisions CRT and Readout Electrostatic deflection Calibrated area of 10 divisions by 10 divisions 12 usable divisions horizontally 1 division equals 1 cm 4000 V Automatic digitally lighted display Readout is automatically blanked if readings would be outside the avail able ranges or would give erroneous display 1 nA to 20 A calculated from VER TICAL switch setting DISPLAY OFFSET Selector switch setting and MODE switch setting or X10 Vertical Interface input 5 mV to 200 V calculated from HORIZONTAL switch setting and DISPLAY OFFSET Selector switch setting 5 nA to 2A and 5 mV to 20 V cal culated from AMPLITUDE switch setting and 1X STEP MULT but ton position or X10 Step Interface Input 3 B or gm PER DIV 1 u to 500 k calculated from VER TICAL switch setting DISPLAY OFFSET
67. ton is pressed Selects rate at which steps are genera ted NORM Provides normal Step Gen erator rate of 1X normal Collector Supply rate 120 steps per second for 60 Hz line frequency 2X Provides rate of two times nor mal rate bX Provides rate of one half nor mal rate 2X and 5X When buttons are pressed together provides normal rate but with step transistions OC curing at peak of Collector Supply sweep 2X and 5X Provides normal rate but with step transitions occurring at peak of Collector Supply sweep STEP OFFSET Allows change of polarity of Step Gen POLARITY IN erator output from polarity set by VERT Button POLARITY switch STEP MULT 1X Provides O 1 times multiplication of Button step amplitude but does not effect offset Standard Test Fixture Controls Terminal Selector Selects way in which Step Generator Is Switch applied to Device Under Test In all positions Collector Supply output is connected to Collector terminal EMITTER GROUNDED Emittter of Device Under Test is connected to ground STEP GEN Step Generator is applied to base terminal of Device Under Test Normal op erating position OPEN OR EXT Base terminal of Device Under Test open Ex ternal signal applied to EXT BASE OR EMIT INPUT connec tor will be applied to base ter minal SHORT Base terminal of De vice Under Test is shorted to emitter terminal BASE GROUNDED Base terminal of Device Under Test is connected to
68. trument and on the front panel of the standard test fixture see Figs 2 2 and 2 3 In addition readout of some of the instrument functions has been pro vided on the front panel Familiarity with the function and use of each of these controls connectors and the readout is necessary for effective operation of the instrument The functions are described in the following table CRT and Readout Controls INTENSITY Controls brightness of display Control FOCUS Provides adjustment for optimum dis Control play definition READOUT Controls brightness of readout Operating Instructions T ype 576 Fig 2 3 Rear panel controls ILLUM Control SCALE ILLUM Control Connector CAMERA POWER Connector Readouts PER VERT DIV Readout PER HORIZ DIV Readout PER STEP Readout B OR gm PER DIV Readout Controls graticule illumination Provides 15 volts for operation of camera Readout indicates deflection factor of vertical display as viewed on CRT Readout indicates deflection factor of horizontal display as viewed on CRT Readout indicates amplitude per step of Step Generator output Readout indicates beta or trans conductance per division of CRT dis play Display Sensitivity and Positioning VERTICAL CURRENT DIV Switch Selects vertical deflection factor of dis play COLLECTOR Normal operation of instrument Vertical display rep resents collector current Use black units to det
69. tton has no effect on steps and offset polarity Repetitive families of characteristic curves generated with REP STEP FAMILY button pressed Single family of characteristic curves gen erated each time SINGLE STEP FAMILY button is pressed Ranges from 1 to 10 as selected by the NUMBER OF STEPS switch For zero steps press SINGLE STEP FAMILY button Display Amplifiers Display Accuracies of Highest On Screen Value Normal and DC Collector Supply Modes Vertical Col lector Current External Vert ical Through Interface Horizontal Col lector Volts Horizontal Base Volts Display magnified DIS Display PLAY OFFSET Selec Unmag tor switch set to either nified VERT X10 or HORIZ X10 and offset be tween 100 and 35 and AO divi 15 divi i l M 3 External Hori zontal Through Interface Leakage Collector Supply Mode Vertical Emitter Current VERT ICAL Switch set between 10 nA and 2 mA Vertical Emitter Current VERT ICAL Switch set to b nA 2 nA or 1 nA Horizontal Collector or Base Volts VERTICAL switch set to 1 WA or more 100 nA 10 nA or 1 nA 500 nA 50 nA or 5 nA 200 nA 20 nA or 2 nA Step Generator Display 2 1 396 1 496 1 t nA nA nA nA Specification T ype 576 l 3 5 TINA Not Applicable 2 3 4 3 Not Applicable 3 plus Not Applicable Not Applicable 0 025 V for each vertical division of
70. tween 10 mA and 20 Current mA 0 5 or less of AMPLITUDE switch setting or 2 mV peak to peak Ripple Plus Noise Front panel RATE button labels in parentheses 1 times 5X 2 times NORM and 4 times 2X line fre quency Steps occur at zero collec tor voltage when 5X or NORM RATE buttons are pressed and also at peak voltage when 2X RATE button is pressed Steps occur at collector voltage peak and at Step Rates normal rate when 5X and 2X RATE buttons are pressed together Pulsed Steps Pulsed steps 80 us or 300 us wide within 20 5 produced when ever one of the PULSED STEPS buttons is pressed Pulsed steps can be produced only at normal and 5 times normal rates Collector Supply mode automatically be comes DC when either the 300 us or 80 us PULSED STEPS button is pressed unless POLARITY switch is set to AC If the 300 Us and 80 us PULSED STEPS buttons are press ed together 300 us pulsed steps are produced but collector supply mode does not change e den Steps and Offset Polarity Step Families Number of Steps Corresponds with collector supply polarity positive going when PO LARITY switch is set to AC when the POLARITY INVERT button is released Is opposite collector sup ply polarity negative going in AC when either the POLARITY IN VERT button is pressed or the Lead Selector switch is set to BASE GROUNDED If Lead Selector switch is set to BASE GROUND ED POLARITY INVERT bu
71. ut the Voltage Selector switch bar see Fig 2 1 turn it 180 and plug it back into the remaining holes Change the line cord power plug to match the power source receptacle or use a 115 to 230 volt adapter 4 To change regulating ranges pull out the Range Se lector switch bar see Fig 2 1 slide it to the desired posi tion and plug it back in Select a ranae which is centered about the average line voltage to which the instrument is to be connected see Table 2 1 o Re install the cover and tighten the two captive Screws 6 o convert from operation with 60 Hz line frequency to operation with 50 Hz line frequency or vice versa slide the 60 Hz 50 Hz switch see Fig 2 1 to the position which coincides with the line frequency being used Before applying power to the instrument check that the indicating tabs on the switch bars are protruding through the correct holes in the voltage selector assembly cover for the desired line voltage and regulating range CAUTION The Type 576 should not be operated with the Volt age Selector switch or the Range Selector switch in the wrong position for the line voltage applied Operation of the instrument with either of these switches in the wrong position will cause incorrect operation and may damage the instrument CONTROLS CONNECTORS AND READOUT All controls and connectors required for normal opera tion of the Type 576 are located on the front and rear panels of the ins
72. utput are displayed vertically The vertical display shows one step per division and the amplitude of each step as shown by the PER STEP readout determines the vertical deflection factor 1t should be noted that if the HORIZONTAL switch is set to STEP GEN the Step Generator output signal is not available for display vertically In this case setting the VERTICAL switch to STEP GEN causes zero vertical signal to be dis played The vertical sensitivity can be increased by 10 times for any of the previously mentioned measurements by setting the DISPLAY OFFSET Selector switch to VERT X10 The magnified vertical deflection factor can be determined either from the PER VERT DIV readout or by dividing the setting of the VERTICAL switch by 10 Horizontal Measurement and Deflection Factor In the horizontal dimension the display on the CRT measures either collector to emitter voltage VCE collec tor to base voltage Vcp base to emitter voltage VBE emitter to base voltage MER or the Step Generator out put The HORIZONTAL switch the Terminal Selector switch and the parameter being measured vertically deter mine what is measured horizontally The PER VERT DIV readout does not indicate deflection fac tors less than 1 nA division The horizontal deflection factor of the display on the CRT is controlled by the HORIZONTAL switch and the DISPLAY OFFSET Selector switch The PER HORIZ DIV readout to the right of the CRT indicate
73. ve box must be installed over the accessories con nectors see Fig 2 7 When the protective box is in place and the lid closed the yellow light turns off and the red light turns on The red light indicates that the Collector Supply is enabled and that a dangerous voltage may appear at the Collector terminals For further information about the interlock system see the Circuit Description Step Generator The Step Generator provides current or voltage which may be applied to the base or the emitter of the device under test The output of the Step Generator is families of ascending steps of current or voltage see Fig 2 24 When these steps together with the Collector Supply output are applied to the device under test families of characteristic curves of the device are displayed on the CRT The NUMBER OF STEPS switch determines the number of steps per family and has a range of from 1 step to 10 steps The AMPLITUDE switch determines the amplitude of each step and provides both current steps and voltage steps The range of step amplitudes available are from 50 nA step to 200 mA step for current steps and from 5 mV step to 2 V step for voltage steps The STEP MULT 1X button when pressed divides the step amplitude by 10 When voltage steps are being applied to the base of a transistor the base current increases very rapidly with increasing base voltage note Caution on front panel To avoid damage to the transistor when using voltage steps
74. voltage characteristics of a tunnel diode or a back diode such as the peak point and valley point currents and voltages put the cathode of the diode in the emitter terminal of the test socket and the anode of the diode in the collector terminal Apply voltage to the device with the VARIABLE COLLECTOR SUPPLY control For most accurate measurements of peak and valley points use the magnified display offset as described in steps 42 through 46 of the First Time Operation Instructions Current and voltage in the reverse direction are measured in the same manner as in the forward direction except that the POLARITY switch is set to PNP For a display of currents nd voltages in both directions set the POLARITY switch to AC 2 33 This page intentionally blank INSIDE BACK COVER OUTSIDE BACK COVER Tektronix 576 Curve Tracer User and Service Manual
75. witch set to NORM when the CAL button is pressed a calibration ref erence spot appears on the CRT This spot represents a signal applied to both the vertical and the horizontal dis play amplifiers which should cause 10 divisions deflection on the CRT graticule both vertically and horizontally If the position of this spot is compared with the position of the spot obtained when the ZERO button is pressed the accuracy of calibration of the display amplifiers can be de termined When the DISPLAY OFFSET Selector switch is set to either VERT or HORIZ the calibration reference spot should appear on the vertical centerline horizontal offset or the horizontal centerline vertical offset as suming the zero reference point is properly adjusted This calibration check should be made with the DISPLAY OFF SET Selector switch in either HORIZ X10 or VERT X10 Any departure of the calibration reference spot from the centerline when this check is made represents an error of 196 per division in the display offset 2 18 The DISPLAY INVERT button provides a means of in verting the display on the CRT When the DISPLAY IN VERT button is pushed the inputs to the display amplifiers are reversed causing the display on the CRT to be inverted both vertically and horizontally about the center of the graticule If the position controls are centered the zero and calibration references spots should appear in particular positions on the graticule dependi

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