±15 kV ESD-Protected, 3.3 V,12 Mbps, EIA RS-485/RS-422 Transceiver ADM3485E FEATURES FUNCTIONAL BLOCK DIAGRAM TIA/EIA RS-485/RS-422 compliant ±15 kV ESD protection on RS-485 input/output pins ADM3485E 12 Mbps data rate Half-duplex transceiver RO R Up to 32 nodes on the bus Receiver open-circuit, fail-safe design Low power shutdown current RE B Outputs high-Z when disabled or powered off Common-mode input range: −7 V to +12 V A DE Thermal shutdown and short-circuit protection Industry-standard 75176 pinout 8-lead narrow SOIC package DI D APPLICATIONS Power/energy metering Telecommunications 03338-001 EMI-sensitive systems Figure 1. Industrial control Local area networks GENERAL DESCRIPTION The ADM3485E is a 3.3 V, low power data transceiver with should be enabled at any time, the output of a disabled or ±15 kV ESD protection, suitable for half-duplex communi- powered-down driver is tristated to avoid overloading the bus. cation on multipoint bus transmission lines. The ADM3485E The receiver has a fail-safe feature that ensures a logic high is designed for balanced data transmission and complies with output when the inputs are floating. Excessive power dissipation TIA/EIA standards RS­485 and RS-422. The ADM3485E is a caused by bus contention or by output shorting is prevented half-duplex transceiver that shares differential lines and has with a thermal shutdown circuit. separate enable inputs for the driver and the receiver. The part is fully specified over the industrial temperature range The devices have a 12 kΩ receiver input impedance, which and is available in an 8-lead narrow SOIC package. allows up to 32 transceivers on a bus. Because only one driver Rev. D 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 One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A. 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. Tel: 781.329.4700 www.analog.com Trademarks and registered trademarks are the property of their respective owners. Fax: 781.461.3113 ©2000-2010 Analog Devices, Inc. All rights reserved.

ADM3485E TABLE OF CONTENTS Features .............................................................................................. 1 Test Circuits and Switching Characteristics ...................................7 Applications ....................................................................................... 1 Typical Performance Characteristics ..............................................9 Functional Block Diagram .............................................................. 1 Standards and Testing .................................................................... 11 General Description ......................................................................... 1 ESD Testing ................................................................................. 11 Revision History ............................................................................... 2 Applications Information .............................................................. 12 Specifications ..................................................................................... 3 Differential Data Transmission ................................................ 12 Timing Specifications ....................................................................... 4 Cable and Data Rate ................................................................... 12 Absolute Maximum Ratings ............................................................ 5 Receiver Open-Circuit Fail-Safe ............................................... 12 Thermal Resistance ...................................................................... 5 Outline Dimensions ....................................................................... 13 ESD Caution .................................................................................. 5 Ordering Guide .......................................................................... 13 Pin Configuration and Pin Function Descriptions ...................... 6 REVISION HISTORY 8/10—Rev. C to Rev. D Changes to Table 1, Driver, Logic Inputs ...................................... 3 12/06—Rev. B to Rev. C Updated Format .................................................................. Universal Removed PDIP Model ....................................................... Universal Changes to Features, Applications, and General Description .... 1 Changes to Specifications ................................................................ 3 Changes to Timing Specifications .................................................. 4 Changes to Absolute Maximum Ratings ....................................... 5 Reorganized Test Circuits and Switching Characteristics Section ..................................................................... 7 Replaced Figure 3 to Figure 11 ....................................................... 7 Deleted Figure 12 to Figure 14 ........................................................ 8 Changes to Figure 15 to Figure 20 .................................................. 9 Changes to Figure 21 and Figure 22 ............................................. 10 Changes to Table 9 .......................................................................... 11 Deleted Figure 24 ............................................................................ 11 Removed Fast Transient Burst Immunity (IEC1000-4-4) Section ................................................................... 12 Updated Outline Dimensions ....................................................... 13 Changes to Ordering Guide .......................................................... 13 10/04—Rev. A to Rev. B Updated Format .................................................................. Universal Changes to Power-Supply Current, Table 1 .................................. 3 Updated Outline Dimensions ....................................................... 14 Changes to Ordering Guide .......................................................... 14 5/00—Rev. 0 to Rev. A Rev. D | Page 2 of 16

ADM3485E SPECIFICATIONS V = +3.3 V ± 0.3 V. All specifications T to T , unless otherwise noted. CC MIN MAX Table 1. Parameter Symbol Min Typ Max Unit Test Conditions/Comments DRIVER Differential Outputs Differential Output Voltage V 2.0 V R = 100 Ω (RS-422) (see Figure 3) OD L 1.5 V R = 54 Ω (RS-485) (see Figure 3) L 1.5 V R = 60 Ω (RS-485) (see Figure 4) L ∆|V | for Complementary Output States1 ∆V 0.2 V R = 54 Ω or 100 Ω (see Figure 3) OD OD L Common-Mode Output Voltage V 3 V R = 54 Ω or 100 Ω ( see Figure 3) OC L ∆|V | for Complementary Output States1 ∆V 0.2 V R = 54 Ω or 100 Ω (see Figure 3) OC OC L Short-Circuit Output Current I –250 mA V = –7 V OSD OUT 250 mA V = 12 V OUT Logic Inputs Input Low Voltage V 0.8 V DE, DI, RE IL Input High Voltage V 2.0 V DE, DI, RE IH Logic Input Current I ±2 µA DE, DI, RE IN1 RECEIVER Differential Inputs Differential Input Threshold Voltage V –0.2 +0.2 V –7 V < V < +12 V TH CM Input Voltage Hysteresis ∆V 50 mV V = 0 V TH CM Input Resistance (A, B) R 12 kΩ –7 V < V < +12 V IN CM Input Current (A, B) I 1.0 mA DE = 0 V, V = 0 V or 3.6 V, V = 12 V IN2 CC IN –0.8 mA DE = 0 V, V = 0 V or 3.6 V, V = –7 V CC IN RO Logic Output Output Voltage High V V – 0.4 V V I = –1.5 mA, V = 200 mV (see Figure 5) OH CC OUT ID Output Voltage Low V 0.4 V I = 2.5 mA, V = 200 mV (see Figure 5) OL OUT ID Short-Circuit Output Current I ±8 ±60 mA 0 V < V < V OSR RO CC Tristate Output Leakage Current I ±1 µA V = 3.6 V, 0 V < V < V OZR CC OUT CC POWER SUPPLY CURRENT Voltage Range V 3.0 3.6 V CC Supply Current I 1.1 2.2 mA No load, DI = 0 V or V , DE = V , CC CC CC RE = 0 V or V CC 0.95 1.9 mA No load, DI = 0 V or V , DE = 0 V, CC RE = 0 V Shutdown Current I 0.002 1 µA DE = 0 V, RE = V , DI = 0 V or V SHDN CC CC ESD PROTECTION A, B Pins ±15 kV Human body model All Pins Except A, B ±4 kV Human body model 1 Δ|VOD| and Δ|VOC| are the changes in VOD and VOC, respectively, when DI input changes state. Rev. D | Page 3 of 16

ADM3485E TIMING SPECIFICATIONS V = 3.3 V, T = 25°C. CC A Table 2. Parameter Symbol Min Typ Max Unit Test Conditions/Comments DRIVER Maximum Data Rate 12 15 Differential Output Delay t 1 22 35 ns R = 60 Ω, C = C = 15 pF (see Figure 6) DD L L1 L2 Differential Output Transition Time t 3 11 25 ns R = 60 Ω, C = C = 15 pF (see Figure 6) TD L L1 L2 Propagation Delay From Low to High Level t 7 23 35 ns R = 27 Ω (see Figure 7) PLH L From High to Low Level t 7 23 35 ns R = 27 Ω (see Figure 7) PHL L |t − t | Propagation Delay Skew t –1.4 ±8 ns R = 27 Ω (see Figure 7) PLH PHL PDS L Enable/Disable Timing Enable Time to Low Level t 42 90 ns R = 110 Ω (see Figure 9) PZL L Enable Time to High Level t 42 90 ns R = 110 Ω (see Figure 8) PZH L Disable Time from Low Level t 35 80 ns R = 110 Ω (see Figure 9) PLZ L Disable Time from High Level t 35 80 ns R = 110 Ω (see Figure 8) PHZ L Enable Time from Shutdown to Low Level t 650 900 ns R = 110 Ω (see Figure 9) PSL L Enable Time from Shutdown to High Level t 650 900 ns R = 110 Ω (see Figure 8) PSH L RECEIVER Propagation Delay From Low to High Level t 25 62 90 ns V = 0 V to 3.0 V, C = 15 pF (see Figure 10) RPLH ID L From High to Low Level t 25 62 90 ns V = 0 V to 3.0 V, C = 15 pF (see Figure 10) RPHL ID L |t − t | Propagation Delay Skew t 6 ±10 ns V = 0 V to 3.0 V, C = 15 pF (see Figure 10) RPLH RPHL RPDS ID L Enable/Disable Timing Enable Time to Low Level t 25 50 ns C = 15 pF (see Figure 11) RPZL L Enable Time to High Level t 25 50 ns C = 15 pF (see Figure 11) RPZH L Disable Time from Low Level t 25 45 ns C = 15 pF (see Figure 11) RPLZ L Disable Time from High Level t 25 45 ns C = 15 pF (see Figure 11) RPHZ L Enable Time from Shutdown to Low Level t 720 1400 ns C = 15 pF (see Figure 11) RPSL L Enable Time from Shutdown to High Level t 720 1400 ns C = 15 pF (see Figure 11) RPSH L Time to Shutdown1 t 80 190 300 ns SHDN 1 The transceivers are put into shutdown mode by bringing the RE high and the DE low. If the inputs are in this state for less than 80 ns, the parts are guaranteed not to enter shutdown. If the parts are in this state for 300 ns or more, the parts are guaranteed to enter shutdown. Rev. D | Page 4 of 16

ADM3485E ABSOLUTE MAXIMUM RATINGS T = 25°C, unless otherwise noted. THERMAL RESISTANCE A θ is specified for the worst-case conditions, that is, a device Table 3. JA soldered in a circuit board for surface-mount packages. Parameter Values V to GND –0.3 V to +6 V CC Table 4. Thermal Resistance Digital Input/Output Voltage (DE, RE, DI) –0.3 V to +6 V Package Type θ Unit JA Receiver Output Voltage (RO) –0.3 V to (V + 0.3 V) CC 8-Lead SOIC_N 158 °C/W Driver Output (A, B)/ Receiver Input (A, B) Voltage −8 V to +13 V Driver Output Current ±250 mA ESD CAUTION Power Dissipation (8-Lead SOIC_N) 650 mW Operating Temperature Range –40°C to +85°C Storage Temperature Range –65°C to +150°C Lead Temperature, Soldering (10 sec) 300°C Vapor Phase (60 sec) 215°C Infrared (15 sec) 220°C ESD Rating Human Body Model (A, B) ±15 kV 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. Rev. D | Page 5 of 16

ADM3485E PIN CONFIGURATION AND PIN FUNCTION DESCRIPTIONS RO 1 8 VCC RE 2 ADM3485E 7 B DDEI 34 (NToOt Pto V SIEcaWle) 65 AGND 03338-002 Figure 2. SOIC_N Pin Configuration (R-8) Table 5. Pin Function Descriptions Pin Mnemonic Number Description RO 1 Receiver Output. When enabled, if A > B by 200 mV, then RO = high. If A < B by 200 mV, then RO = low. RE 2 Receiver Output Enable. With RE low, the receiver output (RO) is enabled. With RE high, the output goes into a high impedance state. If RE is high and DE is low, the ADM3485E enters a shutdown state. DE 3 Driver Output Enable. A high level enables the driver differential outputs A and B. A low level places it in a high impedance state. DI 4 Driver Input. When the driver is enabled, a logic low on DI forces A low and B high, while a logic high on DI forces A high and B low. GND 5 Ground Connection, 0 V. A 6 Noninverting Receiver Input A/Driver Output A. B 7 Inverting Receiver Input B/Driver Output B. V 8 Power Supply, 3.3 V ± 0.3 V. CC Rev. D | Page 6 of 16

ADM3485E TEST CIRCUITS AND SWITCHING CHARACTERISTICS VOM A RL/2 RL = 27Ω S1 VOD D OUT B RL/2 VOC 03338-037 GENERATOR1 50Ω CL = 15pF2 Figure 3. Driver Differential Output Voltage and VCC Common-Mode Output Voltage VOH + VOL VOM = 2 ≈ 1.5V 375Ω 1PPR = 250kHz, 50% DUTY CYCLE,tR ≤ 6.0ns, ZO = 50Ω. VCM = 2CL INCLUDES PROBE AND STRAY CAPACITANCE. –7V TO +12V D VOD RL 3V VCC 375Ω 03338-038 IN 1.5V 1.5V 0V Figure 4. Driver Differential Output Voltage with Varying Common-Mode Voltage tPLH tPHL VOH OAUT VOM VOM VOL VID R tPHL tPLH VOH 0 VOL I(O+L) VOH I(O–H) 03338-039 OBUT VOM VOM VOL 03338-041 Figure 5. Receiver Output Voltage High and Output Voltage Low Figure 7. Driver Propagation Delays CL S1 0V OR 3V D OUT D R60LΩ = OUT CL = 50pF2 RL = 110Ω GENERATOR1 50Ω VCC GENERATOR1 50Ω CL = 15pF2 VOH + VOL VOM = 2 ≈ 1.5V 1PPR = 250kHz, 50% DUTY CYCLE,tR ≤ 6.0ns, ZO = 50Ω. 2CL INCLUDES PROBE AND STRAY CAPACITANCE. 1PPR = 250kHz, 50% DUTY CYCLE,tR ≤ 6.0ns, ZO = 50Ω. 2CL INCLUDES PROBE AND STRAY CAPACITANCE. +3V IN +1.5V +1.5V 3V 0V IN 1.5V 1.5V tDD tDD 0V 90% 90% ≈ +2V tPZH tPHZ OUT 1500%% tTD 5100%%tTD ≈ –2V 03338-040 OUT VOM 0.25V 0VVOH 03338-042 Figure 6. Driver Differential Output Delay and Transition Times Figure 8. Driver Enable and Disable Times (tPZH, tPSH, tPHZ) Rev. D | Page 7 of 16

ADM3485E VCC RL = 110Ω S1 0V OR 3V D OUT VID R OUT CL = 50pF2 GENERATOR1 50Ω CL = 15pF2 GENERATOR1 50Ω 1.5V VCC 0V VOM = 2 1PPR = 250kHz, 50% DUTY CYCLE,tR ≤ 6.0ns, ZO = 50Ω. 1PPR = 250kHz, 50% DUTY CYCLE,tR ≤ 6.0ns, ZO = 50Ω. 2CL INCLUDES PROBE AND STRAY CAPACITANCE. 2CL INCLUDES PROBE AND STRAY CAPACITANCE. 3V 3V IN 1.5V 1.5V IN 1.5V 1.5V 0V 0V tPSL tPLZ tRPLH tRPHL VCC OUT VOM 0.25V VOL 03338-043 OUT VOM VOM V0VCC 03338-044 Figure 9. Driver Enable and Disable Times (tPZL, tPSL, tPLZ) Figure 10. Receiver Propagation Delays S1 +1.5V S3 1kΩ VCC –1.5V VID R S2 CL2 GENERATOR1 50Ω 1PPR = 250kHz, 50% DUTY CYCLE,tR ≤ 6.0ns, ZO = 50Ω. 2CL INCLUDES PROBE AND STRAY CAPACITANCE. +3V +3V S1 OPEN S1 CLOSED IN +1.5V S2 CLOSED IN +1.5V S2 OPEN S3 = +1.5V S3 = –1.5V 0V 0V tRPZH tRPZL tRPSH tRPSL VOH VCC OUT +1.5V OUT +1.5V 0V VOL +3V +3V S1 OPEN S1 CLOSED IN +1.5V S2 CLOSED IN +1.5V S2 OPEN S3 = +1.5V S3 = –1.5V 0V 0V tRPHZ tRPLZ OUT VOH VCC OUT +0.25V 0V +0.25V VOL 03338-045 Figure 11. Receiver Enable and Disable Times Rev. D | Page 8 of 16

ADM3485E TYPICAL PERFORMANCE CHARACTERISTICS 25 0.8 IRO = 2.5mA 0.7 20 URRENT (mA) 15 W VOLTAGE (V) 000...456 OUTPUT C 10 OUTPUT LO 00..23 5 0.1 0 0 0 0.5 1O.0UTPUT1 L.5OW VO2L.0TAGE (V2.)5 3.0 3.5 03338-051 –40 TE1M0PERATURE (°C) 60 85 03338-054 Figure 12. Output Current vs. Receiver Output Low Voltage Figure 15. Receiver Output Low Voltage vs. Temperature –18 100 –16 90 80 –14 mA) mA) 70 T ( –12 T ( N N 60 RE –10 RE UR UR 50 UT C –8 UT C 40 P P T –6 T U U 30 O O –4 20 –2 10 0 0 0 0.5 1O.0UTPUT1 H.5IGH VO2L.0TAGE (2V.)5 3.0 3.5 03338-052 0 0.5 DIFF1E.0RENTIA1L.5 OUTPU2T.0 VOLTA2G.5E (V) 3.0 3.5 03338-055 Figure 13. Output Current vs. Receiver Output High Voltage Figure 16. Driver Output Current vs. Differential Output Voltage 3.30 2.6 IRO = –1.5mA RL = 54Ω 2.5 V) AGE (V)33..2205 VOLTAGE ( 22..43 OLT UT 2.2 H V3.15 UTP 2.1 G O TPUT HI3.10 ENTIAL 21..09 U R O E F 1.8 3.05 F DI 1.7 3.00 1.6 –50 –25 TE0MPERATU2R5E (°C) 50 75 03338-053 –50 –25 TE0MPERATU2R5E (°C) 50 75 03338-056 Figure 14. Receiver Output High Voltage vs. Temperature Figure 17. Driver Differential Output Voltage vs. Temperature Rev. D | Page 9 of 16

ADM3485E 120 0.9 0.8 100 A) 0.7 T CURRENT (mA) 6800 WN CURRENT (µ 000...654 U O TP 40 TD 0.3 U U O H S 0.2 20 0.1 0 0 0 2 OU4TPUT LOW6 VOLTAGE8 (V) 10 12 03338-057 –50 –25 TE0MPERATU2R5E (°C) 50 75 03338-060 Figure 18. Output Current vs. Driver Output Low Voltage Figure 21. Shutdown Current vs. Temperature 120 100 A) DI T (m 80 3 N E R UR 60 C A T U TP 40 U O 20 CH1 B CH2 0–7 –6 –5 –O4UTP–3UT H–IG2H V–O1LTAG0E (V)1 2 3 4 03338-058 CCHH31 21..00VV ΩΩ CH2 1.0V Ω IMT 2400n0sp s1/.p2t5GAS / sCH3 1.44V 03338-061 Figure 19. Output Current vs. Driver Output High Voltage Figure 22. Driver Propagation Delay 1.2 1.1 mA) 1.0 VA– VB T ( M1 N E 0.9 R R U C Y 0.8 L P P SU 0.7 RO 0.6 3 0.5–40 –10 TEMPER2A0TURE (°C) 50 80 03338-059 CMHA3T H 21. 0 2V.0Ω1V M 220000nnss 250MS/s 4ns/pt A CH2 1.24V 03338-062 Figure 20. Supply Current vs. Temperature Figure 23. Receiver Propagation Delay, Driven by External RS-485 Device Rev. D | Page 10 of 16

ADM3485E STANDARDS AND TESTING Table 6 compares RS-422 and RS-485 interface standards, and influenced by humidity, temperature, barometric pressure, Table 7 and Table 8 show transmitting and receiving truth tables. distance, and rate of closure of the discharge gun. The contact discharge method, while less realistic, is more repeatable and is Table 6. gaining acceptance and preference over the air-gap method. Specification RS-422 RS-485 Although very little energy is contained within an ESD pulse, Transmission Type Differential Differential the extremely fast rise time, coupled with high voltages, can Maximum Data Rate 10 Mbps 10 Mbps cause failures in unprotected semiconductors. Catastrophic Maximum Cable Length 4000 ft 4000 ft Minimum Driver Output Voltage ±2 V ±1.5 V destruction can occur immediately as a result of arcing or Driver Load Impedance 100 Ω 54 Ω heating. Even if catastrophic failure does not occur immediately, Receiver Input Resistance 4 kΩ min 12 kΩ min the device can suffer from parametric degradation, which can Receiver Input Sensitivity ±200 mV ±200 mV result in degraded performance. The cumulative effects of Receiver Input Voltage Range −7 V to +7 V −7 V to +12 V continuous exposure can eventually lead to complete failure. Number of Drivers/Receivers per Line 1/10 32/32 I/O lines are particularly vulnerable to ESD damage. Simply touching or plugging in an I/O cable can result in a static Table 7. Transmitting Truth Table discharge that can damage or completely destroy the interface Transmitting Inputs Transmitting Outputs product connected to the I/O port. It is extremely important, RE DE DI B A therefore, to have high levels of ESD protection on the I/O lines. X1 1 1 0 1 X1 1 0 1 0 The ESD discharge could induce latch-up in the device under 0 0 X1 High-Z2 High-Z2 test, so it is important that ESD testing on the I/O pins be 1 0 X1 High-Z2 High-Z2 carried out while device power is applied. This type of testing is more representative of a real-world I/O discharge, where the 1 X = don't care. equipment is operating normally when the discharge occurs. 2 High-Z = high impedance. Table 8. Receiving Truth Table Table 9. ESD Test Results Receiving Inputs Receiving Outputs ESD Test Method I/O Pins RE DE A – B RO Human Body Model ±15 kV 0 X1 >+0.2 V 1 0 X1 <–0.2 V 0 100% 0 X1 Inputs open 1 90% 1 X1 X1 High-Z2 1 X = don't care. AK E 2 High-Z = high impedance. IP ESD TESTING 36.8% 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 10% uthsee su an ihti ughnedre rte tsets vt.o Wltaigthe baiurt- gdaope sd insocht amrgaek,e t dhier edcist cchoanrtgaec tg uwnit his tRL tDL TIMEt 03338-023 moved toward the unit under test, developing an arc across the Figure 24. Human Body Model Current Waveform air gap, hence the term air-gap discharge. This method is Rev. D | Page 11 of 16

ADM3485E APPLICATIONS INFORMATION DIFFERENTIAL DATA TRANSMISSION The ADM3485E is designed for bidirectional data communi- cations on multipoint transmission lines. A typical application Differential data transmission is used to reliably transmit data showing a multipoint transmission network is illustrated in at high rates over long distances and through noisy environ- Figure 25. Only one driver can transmit at a particular time, ments. Differential transmission nullifies the effects of ground but multiple receivers may be enabled simultaneously. shifts and noise signals that appear as common-mode voltages on the line. As with any transmission line, it is important that reflections are minimized. This can be achieved by terminating the extreme Two main standards that specify the electrical characteristics of ends of the line using resistors equal to the characteristic impe- transceivers used in differential data transmission are approved dance of the line. Stub lengths off the main line must also be by the Electronics Industries Association (EIA). The RS-422 kept as short as possible. A properly terminated transmission standard specifies data rates up to 10 Mbps and line lengths up line appears purely resistive to the driver. to 4000 feet. A single driver can drive a transmission line with up to 10 receivers. The RS-485 standard was defined to cater to RECEIVER OPEN-CIRCUIT FAIL-SAFE true multipoint communications. This standard meets or The receiver input includes a fail-safe feature that guarantees exceeds all the requirements of RS-422 but also allows multiple a logic high on the receiver when the inputs are open circuit drivers and receivers to be connected to a single bus. An or floating. extended common-mode range of −7 V to +12 V is defined. Table 10. RS-422 and RS-485 Interface Standards The most significant difference between RS-422 and RS-485 is Specification RS-422 RS-485 the fact that under the RS-485 standard the drivers may be Transmission Type Differential Differential disabled, thereby allowing more than one to be connected to a Maximum Cable Length 4000 ft 4000 ft single line. Only one driver should be enabled at a time, but the Minimum Driver Output Voltage ±2 V ±1.5 V RS-485 standard contains additional specifications to guarantee Driver Load Impedance 100 Ω 54 Ω device safety in the event of line contention. Receiver Input Resistance 4 kΩ min 12 kΩ min CABLE AND DATA RATE Receiver Input Sensitivity ±200 mV ±200 mV The transmission line of choice for RS-485 communications is a Receiver Input Voltage Range −7 V to +7 V −7 V to +12 V twisted pair. Twisted-pair cable tends to cancel common-mode noise and also causes cancellation of the magnetic fields generated by the current flowing through each wire, thereby reducing the effective inductance of the pair. ADM3485E ADM3485E RO R R RO A A RE RE DE DE B B DI D D DI A B A B ADM3485E ADM3485E R R D D RO REMAXDIEMUMD INUMBER OF TRANSCEIVERSR OON BRUES: D50E DI 03338-027 Figure 25. Multipoint Transmission Network Rev. D | Page 12 of 16

ADM3485E OUTLINE DIMENSIONS 5.00(0.1968) 4.80(0.1890) 8 5 4.00(0.1574) 6.20(0.2441) 3.80(0.1497) 1 4 5.80(0.2284) 1.27(0.0500) 0.50(0.0196) BSC 1.75(0.0688) 0.25(0.0099) 45° 0.25(0.0098) 1.35(0.0532) 8° 0.10(0.0040) 0° COPLANARITY 0.51(0.0201) 0.10 SEATING 0.31(0.0122) 0.25(0.0098) 10..2470((00..00510507)) PLANE 0.17(0.0067) COMPLIANTTOJEDECSTANDARDSMS-012-AA C(RINOEFNPEATRRREOENNLCLTEIHNEOGSNDELISYM)AEANNRDSEIAORRNOESUNANORDETEDAIN-POMPFRIFLOLMPIMIRLELIATIMTEEERTFSEO;RIRNECUQHSUEDIVIINMAELDENENSSTIIOGSNNFS.OR 012407-A Figure 26. 8-Lead Standard Small Outline Package [SOIC_N] Narrow Body (R-8) Dimensions shown in millimeters and (inches) ORDERING GUIDE Model1 Temperature Range Package Description Package Option ADM3485EAR –40°C to +85°C 8-Lead Standard Small Outline Package [SOIC_N] R-8 ADM3485EAR-REEL7 –40°C to +85°C 8-Lead Standard Small Outline Package [SOIC_N] R-8 ADM3485EAR-REEL –40°C to +85°C 8-Lead Standard Small Outline Package [SOIC_N] R-8 ADM3485EARZ –40°C to +85°C 8-Lead Standard Small Outline Package [SOIC_N] R-8 ADM3485EARZ-REEL7 –40°C to +85°C 8-Lead Standard Small Outline Package [SOIC_N] R-8 ADM3485EARZ-REEL –40°C to +85°C 8-Lead Standard Small Outline Package [SOIC_N] R-8 1 Z = RoHS Compliant Part. Rev. D | Page 13 of 16

ADM3485E NOTES Rev. D | Page 14 of 16

ADM3485E NOTES Rev. D | Page 15 of 16

ADM3485E NOTES ©2000-2010 Analog Devices, Inc. All rights reserved. Trademarks and registered trademarks are the property of their respective owners. D03338-0-8/10(D) Rev. D | Page 16 of 16

Mouser Electronics Authorized Distributor Click to View Pricing, Inventory, Delivery & Lifecycle Information: A nalog Devices Inc.: ADM3485EAR ADM3485EAR-REEL7 ADM3485EARZ ADM3485EARZ-REEL ADM3485EARZ-REEL7