±15 kV ESD Protected, Slew Rate Limited, 5 V, RS-485 Transceiver ADM483E ±15 kV ESD protection 250 kbps data rate Reduced slew rate for low EM interference Single 5 V ± 10% supply −7 V to +12 V bus common-mode range Up to 32 nodes on the bus Receiver open-circuit, fail-safe design Short-circuit protection 36 μA supply current 0.1 μA shutdown current FUNCTIONAL BLOCK DIAGRAM ADM483E RO R B RE DE DI A D 06012-001 FEATURES Figure 1. APPLICATIONS Low power RS-485 systems Electrically harsh environments EMI sensitive applications DTE-DCE interface Packet switching Local area networks GENERAL DESCRIPTION The ADM483E is a 5 V, low power data transceiver with ±15 kV ESD protection suitable for half-duplex communication on multipoint bus transmission lines. The ADM483E is designed for balanced data transmission and complies with TIA/EIA Standards RS-485 and RS-422, which allow up to 32 transceivers on a bus. The ADM483E has a low current shutdown mode in which it consumes only 0.1 μA. Drivers are short-circuit current-limited and are protected against excessive power dissipation by thermal shutdown circuitry that places their outputs into a high impedance state. The receiver input has a fail-safe feature that guarantees a logic high output if the input is open circuit. The ADM483E is fully specified over the industrial temperature ranges and is available in 8-lead SOIC_N packages. Because only one driver is enabled at any time, the output of a disabled or power-down driver is three-stated to avoid overloading the bus. Rev. A Information furnished by Analog Devices is believed to be accurate and reliable. However, no responsibility is assumed by Analog Devices for its use, nor for any infringements of patents or other rights of third parties that may result from its use. Specifications subject to change without notice. No license is granted by implication or otherwise under any patent or patent rights of Analog Devices. Trademarks and registered trademarks are the property of their respective owners. One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A. Tel: 781.329.4700 www.analog.com Fax: 781.461.3113 ©1997–2007 Analog Devices, Inc. All rights reserved. ADM483E TABLE OF CONTENTS Features .............................................................................................. 1 Test Circuits and Switching Characteristics...................................9 Applications....................................................................................... 1 General Information ...................................................................... 11 Functional Block Diagram .............................................................. 1 ESD Transient Protection Scheme ........................................... 11 General Description ......................................................................... 1 ESD Testing ................................................................................. 12 Revision History ............................................................................... 2 Applications Information .............................................................. 13 Specifications..................................................................................... 3 Differential Data Transmission ................................................ 13 Timing Specifications .................................................................. 4 Cable and Data Rate................................................................... 13 Absolute Maximum Ratings............................................................ 5 Outline Dimensions ....................................................................... 14 ESD Caution.................................................................................. 5 Ordering Guide .......................................................................... 14 Pin Configuration and Function Descriptions............................. 6 Typical Performance Characteristics ............................................. 7 REVISION HISTORY 12/07—Rev. 0 to Rev. A Updated Format..................................................................Universal Changes to Features ......................................................................... 1 Changes to General Description .................................................... 1 Changes to Table 1............................................................................ 3 Changes to Table 2............................................................................ 4 Changes to Table 3............................................................................ 5 Changes to Table 5............................................................................ 6 Changes to Typical Performance Characteristics Section........... 7 Changes to Test Circuits and Switching Characteristics Section...9 Changes to General Information Section.................................... 11 Updated Outline Dimensions ....................................................... 14 Changes to Ordering Guide .......................................................... 14 1/97—Revision 0: Initial Version Rev. A | Page 2 of 16 ADM483E SPECIFICATIONS VCC = 5 V ± 10%. All specifications TMIN to TMAX, unless otherwise noted. Table 1. Parameter DRIVER Differential Output Voltage, VOD Min Typ 2.0 1.5 1.5 Δ|VOD| for Complementary Output States Common-Mode Output Voltage, VOC Δ|VOC| for Complementary Output States Output Short-Circuit Current (VOUT = High) Output Short-Circuit Current (VOUT = Low) CMOS Input Logic Threshold Low, VINL CMOS Input Logic Threshold High, VINH Logic Input Current (DE, DI) RECEIVER Differential Input Threshold Voltage, VTH Input Voltage Hysteresis, ΔVTH Input Resistance Input Current (A, B) 2.0 1.4 1.4 Max Unit Test Conditions/Comments 5.0 5.0 5.0 5.0 0.2 3 0.2 250 250 0.8 V V V V V V V mA mA V V μA VCC = 5.25 V; R = ∞, see Figure 15 R = 50 Ω (RS-422), see Figure 15 R = 27 Ω (RS-485), see Figure 15 VIN = –7 V to +12 V R = 27 Ω or 50 Ω, see Figure 15 R = 27 Ω or 50 Ω, see Figure 15 R = 27 Ω or 50 Ω –7 V ≤ VO ≤ +12 V –7 V ≤ VO ≤ +12 V −7 V ≤ VCM ≤ +12 V VCM = 0 V −7 V ≤ VCM ≤ +12 V VIN = 12 V VIN = –7 V 85 ±2.0 V mV kΩ mA mA μA V V mA μA 120 360 10 μA μA μA IOUT = 4.0 mA IOUT = −4.0 mA VOUT = GND or VCC 0.4 V ≤ VOUT ≤ 2.4 V Outputs unloaded, receivers enabled DE = 0 V (disabled), RE = 0 V DE = 5 V (enabled), RE = 0 V DE = 0 V, RE = VCC kV HBM air discharge; Pin A, Pin B ±1.0 −0.2 +0.2 70 12 1 −0.8 Logic Enable Input Current (RE) CMOS Output Voltage Low, VOL CMOS Output Voltage High, VOH Short-Circuit Output Current Three-State Output Leakage Current POWER SUPPLY CURRENT ICC Supply Current in Shutdown ESD IMMUNITY ESD Protection ±1 0.4 4.0 7 36 270 0.1 ±15 Rev. A | Page 3 of 16 ADM483E TIMING SPECIFICATIONS VCC = 5 V ± 10%. All specifications TMIN to TMAX, unless otherwise noted. Table 2. Parameter DRIVER Propagation Delay Input to Output (tPLH, tPHL) Min Max Unit Test Conditions/Comments 2000 ns 800 ns 250 2000 ns 250 300 2000 3000 ns ns RL Diff = 54 Ω, CL1 = CL2 = 100 pF, see Figure 16 and Figure 17 RL Diff = 54 Ω, CL1 = CL2 = 100 pF, see Figure 16 and Figure 17 RL Diff = 54 Ω, CL1 = CL2 = 100 pF, see Figure 16 and Figure 17 RL = 500 Ω, CL = 100 pF, see Figure 18 and Figure 19 RL = 500 Ω, CL = 15 pF, see Figure 18 and Figure 19 2000 50 50 ns ns ns ns RL = 1 kΩ, CL = 15 pF, see Figure 22 RL = 1 kΩ, CL = 15 pF, see Figure 22 3000 5000 5000 ns ns ns RL = 500 Ω, CL = 100 pF, see Figure 18 and Figure 19 RL = 1 kΩ, CL = 15 pF, see Figure 22 250 100 Driver Output to Output (tSKEW) Driver Rise/Fall Time (tR, tF) Driver Enable to Output Valid Driver Disable Timing RECEIVER Propagation Delay Input to Output (tPLH, tPHL) Skew (|tPLH – tPHL|) Receiver Enable (tEN1) Receiver Disable (tEN2) SHUTDOWN Time to Shutdown Driver Enable from Shutdown Receiver Enable from Shutdown Typ 250 200 10 10 50 200 Rev. A | Page 4 of 16 CL = 15 pF, see Figure 20 ADM483E ABSOLUTE MAXIMUM RATINGS TA = 25°C, unless otherwise noted. Table 3. Parameter VCC to GND Digital I/O Voltage (DE, RE) Driver Input Voltage (DI) Receiver Output Voltage (RO) Driver Output/Receiver Input Voltage (Pin A, Pin B) ESD Rating: Air (Human Body Model) (Pin A, Pin B) Power Dissipation 8-Lead SOIC_N θJA, Thermal Impedance Operating Temperature Range Industrial (A Version) Storage Temperature Range Lead Temperature (Soldering, 10 sec) Vapor Phase (60 sec) Infrared (15 sec) Rating −0.5 V to +6 V −0.5 V to (VCC + 0.5 V) −0.5 V to (VCC + 0.5 V) −0.5 V to (VCC + 0.5 V) −9 V to +14 V Stresses above those listed under Absolute Maximum Ratings may cause permanent damage to the device. This is a stress rating only; functional operation of the device at these or any other conditions above those indicated in the operational section of this specification is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability. ESD CAUTION ±15 kV 470 mW 110°C/W −40°C to +85°C −65°C to +150°C 300°C 215°C 220°C Rev. A | Page 5 of 16 ADM483E RO 1 RE 2 ADM483E DE 3 TOP VIEW DI 4 (Not to Scale) 8 VCC 7 B 6 A 5 GND 06012-002 PIN CONFIGURATION AND FUNCTION DESCRIPTIONS Figure 2. Pin Configuration Table 4. Pin Function Descriptions Pin No. 1 2 Mnemonic RO RE 3 DE 4 DI 5 6 7 8 GND A B VCC Description Receiver Output. When enabled, if A > B by 200 mV, then RO = high. If A < B by 200 mV, then RO = low. Receiver Output Enable. A low level enables the receiver output, RO. A high level places the receiver output in a high impedance state. Driver Output Enable. A high level enables the driver differential outputs, A and B. A low level places the driver differential outputs in a high impedance state. Driver Input. When the driver is enabled, a logic low on DI forces A low and B high. A logic high on DI forces A high and B low. Ground Connection, 0 V. Noninverting Receiver Input A/Driver Output A. Inverting Receiver Input B/Driver Output B. Power Supply, 5 V ± 10%. Table 5. Selection Table Part No. ADM483E Duplex Half Data Rate (kbps) 250 Low Power Shutdown Yes Tx/Rx Enable Yes Rev. A | Page 6 of 16 ICC (μA) 36 No. of Tx/Rx on Bus 32 ESD kV ±15 ADM483E TYPICAL PERFORMANCE CHARACTERISTICS 50 0.9 45 0.8 OUTPUT LOW VOLTAGE (V) 35 30 25 20 15 10 0.6 0.5 0.4 0.3 0.2 0.1 5 0 0.5 1.0 1.5 2.0 2.5 OUTPUT LOW VOLTAGE (V) 0 –40 06012-003 0 0.7 –20 0 20 40 60 80 TEMPERATURE (°C) Figure 3. Output Current vs. Receiver Output Low Voltage 06012-006 OUTPUT CURRENT (mA) 40 Figure 6. Receiver Output Low Voltage vs. Temperature 45 –30 40 –25 OUTPUT CURRENT (mA) OUTPUT CURRENT (mA) 35 –20 –15 –10 30 25 20 15 10 –5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 OUTPUT HIGH VOLTAGE (V) 0 06012-004 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 Figure 7. Driver Output Current vs. Differential Output Voltage 2.3 DIFFERENTIAL OUTPUT VOLTAGE (V) 4.5 4.4 4.3 4.2 4.1 4.0 –20 0 20 40 60 80 TEMPERATURE (°C) 2.2 2.1 2.0 1.9 1.8 1.7 1.6 1.5 –40 06012-005 OUTPUT HIGH VOLTAGE (V) 0.5 DIFFERENTIAL OUTPUT VOLTAGE (V) Figure 4. Output Current vs. Receiver Output High Voltage 3.9 –40 0 –20 0 20 40 60 80 TEMPERATURE (°C) Figure 5. Receiver Output High Voltage vs. Temperature Figure 8. Driver Differential Output Voltage vs. Temperature Rev. A | Page 7 of 16 06012-008 0 1.5 06012-007 5 ADM483E 10 140 9 120 SHUTDOWN CURRENT (µA) 80 60 40 7 6 5 4 3 2 20 1 0 2 4 6 8 10 12 OUTPUT LOW VOLTAGE (V) 0 –60 06012-009 0 –40 –20 0 20 40 60 80 100 TEMPERATURE (°C) Figure 9. Output Current vs. Driver Output Low Voltage Figure 12. Shutdown Current vs. Temperature –140 OUTPUT CURRENT (mA) –120 –100 –80 A B 2 –60 –40 RO –20 –4 –2 0 2 4 6 OUTPUT HIGH VOLTAGE (V) CH1 5.00V CH2 500mV CH3 500mV Figure 10. Output Current vs. Driver Output High Voltage M200ns T 57.60% A CH1 2.80V 06012-013 –6 06012-010 1 0 –8 Figure 13. ADM483E Receiver tPHL 600 400 B 300 A 2 200 DE = VCC AND RE = x DE = 0 AND RE = 0 DE = 0 AND RE = VCC RO 1 0 –40 –20 0 20 40 60 TEMPERATURE (°C) 80 CH1 5.00V CH2 500mV CH3 500mV Figure 11. ADM483E Supply Current vs. Temperature M200ns T 60.80% A CH1 Figure 14. ADM483E Receiver tPLH Driven by External RS-485 Device Rev. A | Page 8 of 16 2.80V 06012-014 100 06012-011 SUPPLY CURRENT (µA) 500 06012-012 OUTPUT CURRENT (mA) 8 100 ADM483E TEST CIRCUITS AND SWITCHING CHARACTERISTICS Y VCC RL = 500Ω S1 RL 0V OR 5V D OUT CL VOD VOC GENERATOR 06012-015 RL Z 50Ω Figure 15. Driver DC Test Load 5V DE 5V VCC/2 0V tDZL, tDZL(SHDN) CL 2.3V OUT RL 0.5V VOL B Figure 19. Driver Enable and Disable Times (tDZL, tDLZ, tDZL(SHDN)) 06012-016 CL VID ATE 5V DI tDPLH tDPHL 1/2 VO Figure 20. Receiver Propagation Delay Test Circuit B A +1V A VO B tRPLH 1/2VO VDIFF = V (A) – V (B) 90% RO 90% 10% tDR 1.5V VOL 10% tDF tSKEW = tDPLH – tDPHL Figure 17. Driver Propagation Delays S1 0 OR 5V GENERATOR D OUT CL RL = 500Ω 50Ω 5V DE 1.5V 0V tDZH, tDZH(SHDN) 0.5V VOH 2.3V tDHZ 0V 06012-018 OUT –1V tRPHL VOH 06012-017 +VO VDIFF 0V –VO R A 1.5V 0V RECEIVER OUTPUT B Figure 16. Driver Timing Test Circuit Figure 18. Driver Enable and Disable Times (tDHZ, tDZH, tDZH(SHDN)) Rev. A | Page 9 of 16 THE RISE TIME AND FALL TIME OF INPUT A AND INPUT B < 4ns Figure 21. Receiver Propagation Delays 06012-021 VOD 06012-020 DI tDLZ VCC A 06012-019 DE ADM483E S1 S3 –1.5V 0V OR 5V GENERATOR VCC 1kΩ VID CL 15pF S2 50Ω S1 CLOSED S2 OPEN S3 = –1.5V S1 OPEN S2 CLOSED S3 = +1.5V +5V +5V RE RE 0V tRZH, tRZH(SHDN) tRZL, tRZL(SHDN) +1.5V RO 0V VOL S1 OPEN S2 CLOSED S3 = +1.5V S1 CLOSED S2 OPEN S3 = +1.5V +5V RE +5V RE +1.5V 0V RO +1.5V tRLZ tRHZ +0.5V 0V VCC VOH +1.5V RO +1.5V 0V VCC VOH RO 0V +0.5V Figure 22. Receiver Enable and Disable Times Rev. A | Page 10 of 16 VOL 06012-022 +1.5V ADM483E GENERAL INFORMATION +5V +5V The ADM483E is a robust RS-485 transceiver that operates from a single 5 V supply. 0.1µF It is ideally suited for operation in electrically harsh environments or where cables may be plugged and unplugged. It is also immune to high RF field strengths without special shielding precautions. The ADM483E is intended for balanced data transmission and complies with both EIA Standards RS-485 and RS-422. It contains a differential line driver and a differential line receiver; it is suitable for half-duplex data transmission because the driver and receiver share the same differential pins. RE The receiver has a fail-safe feature that results in a logic high output state if the inputs are unconnected (floating). A high level of robustness is achieved using internal protection circuitry, eliminating the need for external protection components such as transorbs or surge suppressors. VCC VCC B ADM483E B A A ADM483E RS-485/RS-422 LINK DI RO GND GND RE 06012-023 DE DE DI RO The input impedance on the ADM483E is 12 kΩ, allowing up to 32 transceivers on the differential bus. The ADM483E operates from a single 5 V ± 10% power supply. Excessive power dissipation caused by bus contention or by output shorting is prevented by a thermal shutdown circuit. This feature forces the driver output into a high impedance state if, during fault conditions, a significant temperature increase is detected in the internal driver circuitry. 0.1µF Figure 23. Typical Half-Duplex Link Application Table 6 and Table 7 show the truth tables for transmitting and receiving. Table 6. Transmitting Truth Table RE Inputs DE DI B X1 X1 0 1 1 1 0 0 1 0 X1 X1 0 1 High-Z High-Z 1 Outputs A X = don’t care. Low electromagnetic emissions are achieved using slew limited drivers, minimizing interference both conducted and radiated. Table 7. Receiving Truth Table The ADM483E can transmit at data rates up to 250 kbps. RE A typical application for the ADM483E is illustrated in Figure 23. This figure shows a half-duplex link where data may be transferred at rates up to 250 kbps. A terminating resistor is shown at both ends of the link. This termination is not critical because the slew rate is controlled by the ADM483E and reflections are minimized. 0 0 0 1 The communications network can be extended to include multipoint connections as shown in Figure 26. Up to 32 transceivers can be connected to the bus. ESD TRANSIENT PROTECTION SCHEME 1 1 0 High-Z High-Z Inputs DE 0 0 0 0 Outputs A−B RO ≥ +0.2 V ≤ −0.2 V Inputs O/C X1 1 0 1 High-Z X = don’t care. The ADM483E uses protective clamping structures on its inputs and outputs that clamp the voltage to a safe level and dissipate the energy present in ESD (electrostatic discharge). The protection structure achieves ESD protection up to ±15 kV according to the Human Body Model. Rev. A | Page 11 of 16 ADM483E Although very little energy is contained within an ESD pulse, the extremely fast rise time, coupled with high voltages, can cause failures in unprotected semiconductors. Catastrophic destruction may occur immediately as a result of arcing or heating. Even if catastrophic failure does not occur immediately, the device may suffer from parametric degradation, which can result in degraded performance. The cumulative effects of continuous exposure may eventually lead to complete failure. HIGH VOLTAGE GENERATOR It is possible that the ESD discharge could induce latch-up in the device under test. Therefore, it is important that ESD testing on the I/O pins be carried out while device power is applied. This type of testing is more representative of a real-world I/O discharge where the equipment is operating normally when the discharge occurs. 100% 90% 36.8% 10% TIME (t) tRL R2 Figure 25. Human Body Model ESD Current Waveform DEVICE UNDER TEST ESD TEST METHOD R2 C1 HUMAN BODY MODEL 1.5kΩ 100pF Table 8. ADM483E ESD Test Results ESD Test Method Human Body Model: Air Human Body Model: Contact 06012-024 C1 tDL Figure 24. ESD Generator I/O lines are particularly vulnerable to ESD damage. Simply touching or plugging in an I/O cable can result in a static discharge that may damage or completely destroy the interface product connected to the I/O port. Rev. A | Page 12 of 16 I/O Pins ±15 kV ±8 kV 06012-025 Two coupling methods are used for ESD testing: contact discharge and air-gap discharge. Contact discharge calls for a direct connection to the unit being tested. Air-gap discharge uses a higher test voltage but does not make direct contact with the unit under test. With air-gap discharge, the discharge gun is moved toward the unit under test, developing an arc across the air gap. This method is influenced by humidity, temperature, barometric pressure, distance, and rate of closure of the discharge gun. The contact discharge method, though less realistic, is more repeatable and is gaining acceptance and preference over the air-gap method. It is, therefore, extremely important to have high levels of ESD protection on the I/O lines. IPEAK ESD TESTING ADM483E APPLICATIONS INFORMATION DIFFERENTIAL DATA TRANSMISSION CABLE AND DATA RATE Differential data transmission is used to reliably transmit data at high rates over long distances and through noisy environments. Differential transmission nullifies the effects of ground shifts and noise signals that appear as common-mode voltages on the line. There are two main standards approved by the Electronics Industries Association (EIA) that specify the electrical characteristics of transceivers used in differential data transmission. The transmission line of choice for RS-485 communications is a twisted pair. Twisted pair cable tends to cancel common-mode noise and also cancels the magnetic fields generated by the current flowing through each wire, thereby reducing the effective inductance of the pair. To accommodate true multipoint communications, the RS-485 standard was defined. This standard meets or exceeds all the requirements of RS-422 and also allows for up to 32 drivers and 32 receivers to be connected to a single bus. An extended common-mode range of −7 V to +12 V is defined. The most significant difference between RS-422 and RS-485 is the fact that the drivers can be disabled, thereby allowing more than one (32, in fact) to be connected to a single line. Only one driver should be enabled at a time, but the RS-485 standard contains additional specifications to guarantee device safety in the event of line contention. RT RT D Rev. A | Page 13 of 16 D R R D R D R Figure 26. Typical RS-485 Network 06012-026 The RS-422 standard specifies data rates up to 10 MBaud and line lengths up to 4000 feet. A single driver can drive a transmission line with up to 10 receivers. A typical application showing a multipoint transmission network is shown in Figure 26. An RS-485 transmission line can have as many as 32 transceivers on the bus. Only one driver can transmit at a particular time, but multiple receivers can be enabled simultaneously. ADM483E OUTLINE DIMENSIONS 5.00 (0.1968) 4.80 (0.1890) 8 1 5 4 1.27 (0.0500) BSC 0.25 (0.0098) 0.10 (0.0040) COPLANARITY 0.10 SEATING PLANE 6.20 (0.2441) 5.80 (0.2284) 1.75 (0.0688) 1.35 (0.0532) 0.51 (0.0201) 0.31 (0.0122) 0.50 (0.0196) 0.25 (0.0099) 45° 8° 0° 0.25 (0.0098) 0.17 (0.0067) 1.27 (0.0500) 0.40 (0.0157) COMPLIANT TO JEDEC STANDARDS MS-012-A A CONTROLLING DIMENSIONS ARE IN MILLIMETERS; INCH DIMENSIONS (IN PARENTHESES) ARE ROUNDED-OFF MILLIMETER EQUIVALENTS FOR REFERENCE ONLY AND ARE NOT APPROPRIATE FOR USE IN DESIGN. 012407-A 4.00 (0.1574) 3.80 (0.1497) Figure 27. 8-Lead Standard Small Outline Package [SOIC_N] Narrow Body (R-8) Dimensions shown in millimeters and (inches) ORDERING GUIDE Model ADM483EAR ADM483EAR-REEL ADM483EARZ1 ADM483EARZ-REEL1 Temperature Range –40°C to +85°C –40°C to +85°C –40°C to +85°C –40°C to +85°C Package Description 8-Lead Standard Small Outline Package (SOIC_N) 8-Lead Standard Small Outline Package (SOIC_N) 8-Lead Standard Small Outline Package (SOIC_N) 8-Lead Standard Small Outline Package (SOIC_N) 1 Z = RoHS Compliant Part. Rev. A | Page 14 of 16 Package Option R-8 R-8 R-8 R-8 Ordering Quantity 2500 2500 ADM483E NOTES Rev. A | Page 15 of 16 ADM483E NOTES ©1997–2007 Analog Devices, Inc. All rights reserved. Trademarks and registered trademarks are the property of their respective owners. D06012-0-12/07(A) Rev. A | Page 16 of 16