National DS36C278 User's Manual
Contents
1. 0 2V RO 3 5 4 6 V VoL Low Level Output Voltage Io 4 mA Vip 0 2V Figure 11 0 3 0 5 losr Short Circuit Current Vo GND RO 7 35 85 mA lozr TRI STATE Leakage Current Vo 0 4V to 2 4V 1 pA DEVICE CHARACTERISTICS VIH High Level Input Voltage 2 0 Voc V VIL Low Level Input Voltage DE GND 0 8 lH High Level Input Current Vin Voc RE 2 pA lit Low Level Input Current Voc 5V VL OV pI 2 pA Vcc 3 0V 2 pA loc Power Supply Current Driver and Receiver ON 200 500 pA Icop No Load Driver OFF Receiver ON y 200 500 pA Iocp Driver ON Receiver OFF 200 500 pA Iccz Driver and Receiver OFF 200 500 pA Switching Characteristics Over Supply Voltage and Operating Temperature ranges unless otherwise specified Notes 3 and 8 Symbol Parameter Conditions Reference Min Typ Max Units DRIVER CHARACTERISTICS PHLD Differential Propagation R 540 C 100 pF 10 39 80 ig Delay High to Low oS e 0 3 Figures 5 6 SKD Differential Skew 0 1 10 As ItpHLD teLHol r Rise Time 3 25 50 ns f Fall Time 3 25 50 ns PHZ Disable Time High to Z CL 15 pF Figures 7 8 80 200 ns PLZ Disable Time Low to Z RE Figures 9 10 80 200 ns PZH Enable Time Z to High C 100 pF Figures 7 8 50 200 ns PZL Enable Time Z to Low RE L Figures 9 10 65 200 ns http www national com Switching Characteristics continued Over Supply Voltage and Operating Temperature ranges unless otherwise specified Notes 3 a2. DS36C278 General Description The DS36C278 is a low power differential bus line trans ceiver designed to meet the requirements of RS 485 stan dard for multipoint data transmission In addition it is com patible with TIA EIA 422 B The CMOS design offers significant power savings over its bipolar and ALS counterparts without sacrificing ruggedness against ESD damage The device is ideal for use in battery powered or power conscious applications Icc is specified at 500 uA maximum The driver and receiver outputs feature TRI STATE capa vationat Semiconductor December 1995 Low Power Multipoint EIA RS 485 Transceiver Features 100 RS 485 compliant Guaranteed RS 485 device interoperation Low power CMOS design Icc 500 uA max Built in power up down glitch free circuitry Permits live transceiver insertion displacement DIP and SOIC packages available Industrial temperature range On board thermal shutdown circuitry Prevents damage to the device in the event of ex cessive power dissipation 40 C to 85 C TRI STATE is a registered trademark of National Semiconductor Corporation bility The driver outputs operate over the entire common m Wide common mode range 7V to 12V mode range of 7V to 12V Bus contention or fault situa gm Receiver open input fail safet tions that cause excessive power dissipation within the de g 1 4 unit load DS36C278 gt 128 nodes vi
3. 1 5V 1 5V av a T telz teze cc Vec ouT a VoL TL F 12040 15 FIGURE 15 Receiver Enable and Disable Waveforms tpz tpzL S1 1 5V 52 GND TL F 12040 16 FIGURE 16 Receiver Enable and Disable Waveforms tpyz tpzH http www national com Typical Application Information TL F 12040 17 FIGURE 17 Typical RS 485 Bus Interface TABLE I Device Pin Descriptions Pin No Name Description 1 RO Receiver Output When RE Receiver Enable is LOW the receiver is enabled ON if DO RI gt DO RI by 200 mV RO will be HIGH If DO RI lt DO RI by 200 mV RO will be LOW Additionally RO will be HIGH for OPEN Non terminated Inputs 2 RE Receiver Output Enable When RE is LOW the receiver output is enabled When RE is HIGH the receiver output is in TRI STATE OFF 3 DE Driver Output Enable When DE is HIGH the driver outputs are enabled When DE is LOW the driver outputs are in TRI STATE OFF 4 DI Driver Input When DE Driver Enable is HIGH the driver is enabled if DI is LOW then DO RI will be LOW and DO RI will be HIGH If DI is HIGH then DO RI is HIGH and DO RI is LOW 5 GND Ground Connection 6 DO RI Driver Output Receiver Input 485 Bus Pin 7 DO RI Driver Output Receiver Input 485 Bus Pin 8 Voc Positive Power Supply Connection Recommended operating range for Vcc is 4 75V to 5 25V Unit Load A unit load for an RS 485 receiver is defined by the input a
4. 7V 485 190 250 mA RECEIVER CHARACTERISTICS VTH Differential Input High Vo Vou lo 0 4V 0 0 Threshold Voltage 7V lt Vom lt 12V Note 5 0 099 ae v VIL Differential Input Low Vo VoL lo 0 4 mA 422 485 zoal copar 7 Threshold Voltage 7V lt Vom lt 12V j VHST Hysteresis Vom OV Note 6 70 mV Rin Input Resistance 7V lt Vom lt 12V DS36C278T 24 68 kQ Rin Input Resistance 7V lt Vom lt 12V DS36C278 48 68 kQ http www national com Electrical Characteristics Continued Over Supply Voltage and Operating Temperature ranges unless otherwise specified Notes 2 and 3 Symbol Parameter Conditions Reference Min Typ Max Units lin Line Input Current Other Input OV DS36C278 Vin 12V 0 0 19 0 25 mA Note 7 v a eee Vin 7V o 01 0 2 ma oh eee Vn 12v o org 05 ma Vin 7V o 0 1 0 4 mA lING Line Input Current Glitch Other Input OV DS36C278 Vin 12V 0 0 19 0 25 mA Note 7 DE Vi RE Vi Vin 7V o 01 02 ma Vcc 3 0V or OV Ta 25 C DS36C278T Vin 12V o 0 19 0 5 mA Vin 7V o 0 1 0 4 mA IB Input Balance Test RS 5000 422 Note 9 400 mV VoH High Level Output Voltage loH 4 mA Vip
5. S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT DEVICES OR SYSTEMS WITHOUT THE EXPRESS WRITTEN APPROVAL OF THE PRESIDENT OF NATIONAL SEMICONDUCTOR CORPORATION As used herein 1 Life support devices or systems are devices or systems which a are intended for surgical implant into the body or b support or sustain life and whose failure to perform when properly used in accordance with instructions for use provided in the labeling can be reasonably expected to result in a significant injury to the user 2 A critical component is any component of a life support device or system whose failure to perform can be reasonably expected to cause the failure of the life support device or system or to affect its safety or effectiveness National Semiconductor Europe National Semiconductor Corporation N Arlington TX 76017 Tel 1 800 272 9959 Deutsch Tel 49 0 180 530 85 85 Fax 1 800 737 7018 English Tel 49 0 180 532 78 32 Fran ais Tel 49 0 180 532 93 58 http www national com Italiano Tel 49 0 180 534 16 80 1111 West Bardin Road Fax 49 0 180 530 85 86 Email europe support nsc com National Semiconductor Hong Kong Ltd 13th Floor Straight Block Ocean Centre 5 Canton Rd Tsimshatsui Kowloon Hong Kong Tel 852 2737 1600 Fax 852 2736 9960 National Semiconductor Japan Ltd Tel 81 043 299 2308 Fax 81 043 299 2408 National does not assume any
6. 69 1 346 1 753 8 MAX TYP 0 004 0 010 ALL LEADS 0 102 0 254 vo HEEE py SEATING oo A 0 102 9 080 010 alt LEAD TIPS 0 203 0 254 TYP ALL LEADS A PLANE i ak i085 ia l 0 014 0 020 typ 0 356 0 508 1 270 aes ft se FADS 0 203 meine 8 Lead 0 150 Wide Molded Small Outline Package JEDEC Order Number DS36C278TM DS36C278M NS Package Number M08A 9 http www national com DS36C278 Low Power Multipoint EIA RS 485 Transceiver Physical Dimensions inches millimeters Continued 0 373 0 400 9 474 10 16 0 090 g 2 286 0 092 4 el 1 fel fl 0 032 0 005 2 337 0 813 0 127 PIN NO 1 IDENT 2 250 0 005 me sland 6 3540 127 PIN NO 1 IDENT omana TS L2 0 280 0 040 7 172 MIN 0 030 ame OPTION 2 max 1 016 0 039 0 300 0 320 0 762 0 145 0 200 62 8 128 20 1 0 991 3 683 5 080 eo aE Er 3 302 0 127 a5 te 0 125 0 140 A 5 0 065 3 175 3 556 i 0 125 BE 0 020 o09 o0 015___ gt tars 1551 90 4 0 508 0 229 0 381 ay TYP MN 0 040 NOM 0 018 0 003 0 325 7 9325 pote 0 457 0 076 F1 t255 1018 0 100 0 010 le 255 0 3a 2 540 40 254 0 045 0 015 1 143 0 381 i wo 1524 1 270 NOBE REV F 8 Lead 0 300 Wide Molded Dual In Line Package Order Number DS36C278TN DS36C278N NS Package Number NO8E LIFE SUPPORT POLICY NATIONAL
7. ce are handled by a thermal shutdown circuit which forces unit load DS36C278T gt 64 nodes the driver outputs into the high impedance state a j 7 N m ESD human body model 22 kV The receiver incorporates a fail safe circuit which guaran f f 3 m Drop in replacement for tees a high output state when the inputs are left open t LTC485 MAX485 DS75176 DS3695 The DS36C278T is fully specified over the industrial temper i ature range 40 C to 85 C Connection and Logic Diagram Truth Table DRIVER SECTION RE DE DI DO RI DO RI Vec x H H H L DO RI X H L L H X L X Z Z DO RI RECEIVER SECTION ou RE DE RI RI RO TL F 12040 1 L L gt 0 2V H Order Number DS36C278TM DS36C278TN L L lt 0 2V L DS36C278M DS36C278N H L x Z See NS Package Number MO8A or NO8E L L OPEN H Note Non terminated open input only 1996 National Semiconductor Corporation TL F 12040 RRD B30M36 Printed in U S A http www national com HINN 49MOd MOT 8ZZD9ESA 10d 1 S8 SuY VIF U ADAIBDSUBI Absolute Maximum Ratings note 1 Recommended Operating If Military Aerospace specified devices are required Conditions please contact the National Semiconductor Sales Min Typ Max Units Office Distributors for availability and specifications Supply Voltage Vcc 4 75 5 0 5 25 v Supply Voltage Vcc 12V Bus Vol
8. est 7V to 12V TL F 12040 18 ere 1204052 FIGURE 2 Driver Vop3 FIGURE 1 Driver Vop2 and Voc TL F 12040 3 TL F 12040 4 FIGURE 3 Driver Voy and VoL Vtest 7V to 12V FIGURE 4 Driver losp GENERATOR TL F 12040 5 FIGURE 5 Driver Differential Propagation Delay Test Circuit http www national com 4 Parameter Measurement Information continued CP CROSSING POINT Vo DO DO t TL F 12040 6 FIGURE 6 Driver Differential Propagation Delays and Differential Rise and Fall Times DI OV OR 3V GENERATOR S1 to DO for DI 3V S1 to DO for DI 0V TL F 12040 7 FIGURE 7 TRI STATE Test Circuit tpzy tpHz DI OV OR 3V O OUT GENERATOR S1 to DO for DI 0V S1 to DO for DI 3V TL F 12040 9 FIGURE 9 TRI STATE Test Circuit tpz tpLz TL F 12040 11 FIGURE 11 Receiver Voy and VoL 3V DE ov Dh Vou OUT 2 3V Noi 0 59 VOFF GND _ Ff TL F 12040 8 FIGURE 8 TRISTATE Waveforms tpzu tpHz OUT Vo 9 59 TL F 12040 10 FIGURE 10 TRI STATE Waveforms tpz tpLz GENERATOR RO amp RE l TL F 12040 12 FIGURE 12 Receiver Differential Propagation Delay Test Circuit http www national com Parameter Measurement Information continuea TL F 12040 13 FIGURE 13 Receiver Differential Propagation Delay Waveforms V RO cc 1 5V O 1 5V GENERATOR TL F 12040 14 3v RE
9. nd 8 Symbol Parameter Conditions Reference Min Typ Max Units RECEIVER CHARACTERISTICS tPHL Propagation Delay CL 15 pF 30 210 400 ing High to Low tpLH Propagation Delay Figures 12 13 30 190 400 Rs Low to High tsk Skew tpH_ teil 0 20 50 ns tpLz Output Disable Time CL 15 pF 50 150 ns t 55 150 ns PHZ Figures 14 15 16 tPzL Output Enable Time 40 150 ns tPZH 45 150 ns Note 1 Absolute Maximum Ratings are those values beyond which the safety of the device cannot be guaranteed They are not meant to imply that the devices should be operated at these limits The table of Electrical Characteristics specifies conditions of device operation Note 2 Current into device pins is defined as positive Current out of device pins is defined as negative All voltages are referenced to ground except Vop1 and Vope Note 3 All typicals are given for Vcc 5 0V Ta 25 C Note 4 Delta Vop2 and Delta Voc are changes in magnitude of Vop2 and Voc respectively that occur when input changes state Note 5 Threshold parameter limits specified as an algebraic value rather than by magnitude Note 6 Hysteresis defined as Vust VTH VTL Note 7 v includes the receiver input current and driver TRISTATE leakage current Note 8 C includes probe and jig capacitance Note 9 For complete details of test see RS 485 Parameter Measurement Information Yt
10. re 12V at 0 5 mA for the top border and 7V at 0 4 mA for the bottom border see Figure 18 Second for a UL device the top and bottom borders shown in Figure 18 are scaled also Again both O mA reference points at 5V and 3V stay the same The other reference points are 12V the bottom border see Figure 78 The advantage of the 1 UL and 1 4 UL devices is the in creased number of nodes on one bus In a single master multi slave type of application where the number of slaves exceeds 32 the DS36C278 279 280 may save in the cost of extra devices like repeaters extra media like cable and or extra components like resistors The DS36C279 and DS36C280 have an additional feature which offers more advantages The DS36C279 has an auto matic sleep mode function for power conscious applica tions The DS36C280 has a slew rate control for EMI con scious applications Refer to the sleep mode and slew rate control portion of the application information section in the corresponding datasheet for more information on these fea tures TL F 12040 19 FIGURE 18 Input Current vs Input Voltage Operating Range http www national com http www national com Physical Dimensions inches millimeters 0 150 0 157 3 810 3 988 0 010 0 020 y 45 gt 0 254 0 508 i 0 189 0 197 4 800 5 004 0 228 0 244 5 791 6 198 0 010 max 0 254 TYP 0 053 0 0
11. responsibility for use of any circuitry described no circuit patent licenses are implied and National reserves the right at any time without notice to change said circuitry and specifications
12. t 0 25 mA for the top border and 7V at 0 2 mA for current versus the input voltage curve The gray shaded re gion is the defined operating range from 7V to 12V The top border extending from 3V atO mA to 12V at 1 mA is defined as one unit load Likewise the bottom border extending from 5V at 0 mA to 7V at 0 8 mA is also defined as one unit load see Figure 18 An RS 485 driver is capable of driving up to 32 unit loads This allows up to 32 nodes on a single bus Although sufficient for many applica tions it is sometimes desirable to have even more nodes For example an aircraft that has 32 rows with 4 seats per row would benefit from having 128 nodes on one bus This would allow signals to be transferred to and from each indi vidual seat to 1 main station Usually there is one or two less seats in the last row of the aircraft near the restrooms and food storage area This frees the node for the main station The DS36C278 the DS36C279 and the DS36C280 all have Y unit load and 1 4 unit load UL options available These devices will allow up to 64 nodes or 128 nodes guaranteed over temperature depending upon which option is selected The 1 UL option is available in industrial temperature and the 1 UL is available in commercial temperature First for a 1 2 UL device the top and bottom borders shown in Figure 18 are scaled Both 0 mA reference points at 5V and 3V stay the same The other reference points a
13. tage 7 142 vV Input Voltage DE RE amp DI 0 5V to Vcc 0 5V Operating Free Air Temperature Ta Common Mode Vcm DS36C278T 40 25 85 C Driver Output Receiver Input 15V DS36C278 0 25 70 C Input Voltage DO RI DO RI 14V Receiver Output Voltage 0 5V to Vcc 0 5V Maximum Package Power Dissipation 25 C M Package 1190 mW derate 9 5 mW C above 25 C N Package 744 mW derate 6 0 mW C above 25 C Storage Temperature Range 65 C to 150 C Lead Temperature Soldering 4 sec 260 C Electrical Characteristics Over Supply Voltage and Operating Temperature ranges unless otherwise specified Notes 2 and 3 Symbol Parameter Conditions Reference Min Typ Max Units DIFFERENTIAL DRIVER CHARACTERISTICS Vop1 Differential Output Voltage lo 0 mA No Load 1 5 5 0 V 422 Vopo Output Voltage lo 0 mA 485 0 5 0 V Vopo Output Voltage Output to GND 0 5 0 V Vop2 oe ee Voltage RL 509 422 Figure 1 2 0 2 8 V Termination Load RL 270 485 15 23 5 0 v AVop2 Balance of Vop2 RL 279 or 500 Note 4 0 2 0 1 0 2 V Vop2 Vop2 422 485 Vop3 Differential Output Voltage R1 540 R2 3750 x Full Load Vrest 7V to 12V Pane te 20 5 0 Voc pal ane Mode RL 270 485 Figure 1 0 3 0 V utput Voltage RL 502 422 0 3 0 AVoc Balance of Voc RL 270 or Note 4 0 0 Voc Voce RL 500 422 485 ia ne if losp Driver Output Short Circuit Vo 12V 485 Figure 4 200 250 mA Current Vo
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