Datasheet

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High Speed, Half-Duplex

Coupler

Isolated RS-485 Transceiver

Data Sheet

ADM2486

Rev. E Document Feedback

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FEATURES

Half-duplex, isolated RS-485 transceiver

PROFIBUS® compliant

ANSI EIA/TIA 485-A and ISO 8482: 1987(E) compliant

20 Mbps data rate

5 V or 3 V operation (V

DD1

)

High common-mode transient immunity: >25 kV/μs

Isolated DE status output

Receiver open-circuit, fail-safe design

Thermal shutdown protection

50 nodes on bus

Safety and regulatory approvals

UL recognition—2500 V

rms

for 1 minute per UL 1577

CSA Component Acceptance Notice #5A

IEC 609501 800 V

rms

(basic), 400 V

rms

(reinforced)

VDE Certificate of Conformity

DIN V VDE 0884-10 (VDE V 0884-10): 2006-12

IORM

= 560 V peak

Operating temperature range: −40°C to +85°C

Wide body, 16-lead SOIC package

APPLICATIONS

Isolated RS-485/RS-422 interfaces

PROFIBUS networks

Industrial field networks

Multipoint data transmission systems

GENERAL DESCRIPTION

The ADM2486 differential bus transceiver is an integrated,

galvanically isolated component designed for bidirectional

data communication on multipoint bus transmission lines. It

is designed for balanced transmission lines and complies with

ANSI EIA/TIA-485-A and ISO 8482: 1987(E).

The device employs Analog Devices iCoupler® technology to

combine a 3-channel isolator, a three-state differential line

driver, and a differential input receiver into a single package.

The logic side of the device is powered with either a 5 V or a

3 V supply, and the bus side uses an isolated 5 V supply.

FUNCTIONAL BLOCK DIAGRAM

RTS

DD1

GND

DD2

GND

GALVANIC ISOLATION

LOGIC SIDE

TxD

RxD

BUS SIDE

04604-001

ADM2486

Figure 1.

The ADM2486 driver has an active-high enable feature. The

driver differential outputs and the receiver differential inputs

are connected internally to form a differential input/output port

that imposes minimal loading on the bus when the driver is

disabled or when VDD1 or VDD2 = 0 V. Also provided is an

active-high receiver disable feature that causes the receive

output to enter a high impedance state.

The device has current-limiting and thermal shutdown features

to protect against output short circuits and situations where bus

contention may cause excessive power dissipation. The part is

fully specified over the industrial temperature range and is

available in a 16-lead, wide body SOIC package.

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Summary of content (20 pages)

PAGE 1
High Speed, Half-Duplex iCoupler Isolated RS-485 Transceiver ADM2486 Data Sheet FEATURES FUNCTIONAL BLOCK DIAGRAM APPLICATIONS Isolated RS-485/RS-422 interfaces PROFIBUS networks Industrial field networks Multipoint data transmission systems VDD2 VDD1 ADM2486 DE TxD PV RxD BUS SIDE GALVANIC ISOLATION RTS LOGIC SIDE A B RE GND2 GND1 04604-001 Half-duplex, isolated RS-485 transceiver PROFIBUS® compliant ANSI EIA/TIA 485-A and ISO 8482: 1987(E) compliant 20 Mbps data rate 5 V or 3 V operation
PAGE 2
ADM2486 Data Sheet TABLE OF CONTENTS Features .............................................................................................. 1 Switching Characteristics .............................................................. 11 Applications ....................................................................................... 1 Typical Performance Characteristics ........................................... 12 General Description .................................................................
PAGE 3
Data Sheet ADM2486 SPECIFICATIONS 2.7 V ≤ VDD1 ≤ 5.5 V, 4.75 V ≤ VDD2 ≤ 5.25 V, TA = TMIN to TMAX, unless otherwise noted. Table 1. Parameter DRIVER Differential Outputs Differential Output Voltage, VOD 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 Driver Enable Output, DE Pin Output High Voltage Min Typ Max Unit Test Conditions/Comments 2.1 2.1 2.
PAGE 4
ADM2486 Parameter COMMON-MODE TRANSIENT IMMUNITY 1 HIGH FREQUENCY, COMMON-MODE NOISE IMMUNITY 1 Data Sheet Min 25 Typ 100 Max Unit kV/µs mV Test Conditions/Comments VCM = 1 kV, transient magnitude = 800 V VHF = +5 V, −2 V < VTEST2 < +7 V, 1 MHz < fTEST < 50 MHz, see Figure 6 Common-mode transient immunity is the maximum common-mode voltage slew rate that can be sustained while maintaining specification-compliant operation. VCM is the common-mode potential difference between the logic and bus sides.
PAGE 5
Data Sheet ADM2486 TIMING SPECIFICATIONS 2.7 V ≤ VDD1 ≤ 5.5 V, 4.75 V ≤ VDD2 ≤ 5.25 V, TA = TMIN to TMAX, unless otherwise noted. Table 2.
PAGE 6
ADM2486 Data Sheet ADM2486 CHARACTERISTICS PACKAGE CHARACTERISTICS Table 3.
PAGE 7
Data Sheet ADM2486 VDE 0884-10 INSULATION CHARACTERISTICS This isolator is suitable for reinforced electrical isolation only within the safety limit data. Maintenance of the safety data must be ensured by means of protective circuits. An asterisk (*) on the physical package denotes VDE V 0884-10 approval for 560 V peak working voltage. Table 6.
PAGE 8
ADM2486 Data Sheet ABSOLUTE MAXIMUM RATINGS TA = 25°C, unless otherwise noted. All voltages are relative to their respective ground. Table 7. Parameter VDD1 VDD2 Digital Input Voltage (RTS, RE, TxD) Digital Output Voltage RxD DE Driver Output/Receiver Input Voltage Operating Temperature Range Storage Temperature Range Average Output Current per Pin θJA Thermal Impedance Lead Temperature Soldering (10 sec) Vapor Phase (60 sec) Infrared (15 sec) Rating −0.5 V to +7 V −0.5 V to +6 V −0.5 V to VDD1 + 0.
PAGE 9
Data Sheet ADM2486 PIN CONFIGURATION AND FUNCTION DESCRIPTIONS VDD1 1 16 VDD2 GND11 2 15 GND21 14 NC RxD 3 ADM2486 RE 4 TOP VIEW 13 B RTS 5 (Not to Scale) 12 A TxD 6 11 NC PV 7 10 DE GND11 8 9 GND21 NC = NO CONNECT 2 AND PIN 8 ARE INTERNALLY CONNECTED. EITHER OR BOTH MAY BE USED FOR GND1. PIN 9 AND PIN 15 ARE INTERNALLY CONNECTED. EITHER OR BOTH MAY BE USED FOR GND2. 04604-003 1 PIN Figure 2. Pin Configuration Table 8. Pin Function Descriptions Pin No.
PAGE 10
ADM2486 Data Sheet TEST CIRCUITS R CL1 A VOD RLDIFF B CL2 Figure 3. Driver Voltage Measurement 04604-007 VOC 04604-005 R Figure 7. Driver Propagation Delay 375Ω DE 150Ω RTS TxD Figure 4. Driver Voltage Measurement RxD DE RTS VDD1 VDD2 Figure 8.
PAGE 11
Data Sheet ADM2486 SWITCHING CHARACTERISTICS VDD1 0.5VDD1 0V 0.5VDD1 tPALH tPBLH 0.7VDD1 tPBHL tPAHL B RTS 0.5VDD1 0.5VDD1 1/2VO 0.3VDD1 VO tZL tLZ A tSKEW tSKEW VOH VOH + 0.5V VOL tHZ tZH VOL tR tF 2.3V A, B 0V 04604-021 VOH VOH – 0.5V 10% POINT 10% POINT 04604-011 A, B 90% POINT 90% POINT 2.3V A, B tPWD = |tPALH – tPAHL |, |tPBLH – tPBHL | Figure 14. Driver Enable/Disable Timing Figure 12. Driver Propagation Delay, Rise/Fall Timing 0.7VDD1 RE 0.
PAGE 12
ADM2486 Data Sheet TYPICAL PERFORMANCE CHARACTERISTICS 1.4 1.2 SUPPLY CURRENT (mA) IDD1 _RCVR_ENABLE @ 5.5V 1.0 IDD2 _DE_ENABLE @ 5.5V 0.8 1 0.6 2 0.4 25 TEMPERATURE (°C) –40 85 4 04604-029 0 CH1 2.00V CH3 2.00V Figure 16. Unloaded Supply Current vs. Temperature 50 04604-025 0.2 CH2 2.00V CH4 2.00V M20.0ns A CH2 T 6.00000ns 3.12V Figure 19.
PAGE 13
ADM2486 0 4.78 –5 4.76 OUTPUT VOLTAGE (V) –10 –15 –20 –25 4.72 4.70 3.25 3.50 3.75 4.00 4.25 4.50 OUTPUT VOLTAGE (V) 4.75 5.00 5.25 4.66 –40 Figure 22. Output Current vs. Receiver Output High Voltage 04604-033 04604-031 4.68 –30 3.00 –25 –10 20 35 5 TEMPERATURE (°C) 50 65 80 Figure 24. Receiver Output High Voltage vs. Temperature IRxD= −4 mA 0.32 35 30 0.30 25 OUTPUT VOLTAGE (V) OUTPUT CURRENT (mA) 4.74 20 15 10 0.28 0.26 0.24 0.22 0 0 0.25 0.50 0.75 1.00 1.
PAGE 14
ADM2486 Data Sheet CIRCUIT DESCRIPTION Table 9. Transmitting ELECTRICAL ISOLATION In the ADM2486, electrical isolation is implemented on the logic side of the interface. Therefore, the part has two main sections: a digital isolation section and a transceiver section (see Figure 26).
PAGE 15
Data Sheet ADM2486 The receiver input includes a fail-safe feature that guarantees a logic high RxD output when the A and B inputs are floating or open-circuited. Because iCouplers use coreless technology, no magnetic components are present, and the problem of magnetic saturation of the core material does not exist. Therefore, iCouplers have essentially infinite dc field immunity. The following analysis defines the conditions under which this can occur.
PAGE 16
ADM2486 Data Sheet APPLICATIONS INFORMATION PC BOARD LAYOUT VDD1 The ADM2486 isolated RS-485 transceiver requires no external interface circuitry for the logic interfaces. Power supply bypassing is strongly recommended at the input and output supply pins (see Figure 29). Bypass capacitors are most conveniently connected between Pin 1 and Pin 2 for VDD1 and between Pin 15 and Pin 16 for VDD2. The capacitor value should be between 0.01 µF and 0.1 µF.
PAGE 17
Data Sheet ADM2486 ISOLATED POWER SUPPLY CIRCUIT The ADM2486 requires isolated power capable of 5 V at up to approximately 75 mA (this current is dependent on the data rate and termination resistors used) to be supplied between the VDD2 and the GND2 pins. A transformer driver circuit with a center-tapped transformer and LDO can be used to generate the isolated 5 V supply, as shown in Figure 32. The center-tapped transformer provides electrical isolation of the 5 V isolated power supply.
PAGE 18
ADM2486 Data Sheet OUTLINE DIMENSIONS 10.50 (0.4134) 10.10 (0.3976) 9 16 7.60 (0.2992) 7.40 (0.2913) 1.27 (0.0500) BSC 0.30 (0.0118) 0.10 (0.0039) COPLANARITY 0.10 10.65 (0.4193) 10.00 (0.3937) 8 0.51 (0.0201) 0.31 (0.0122) 0.75 (0.0295) 45° 0.25 (0.0098) 2.65 (0.1043) 2.35 (0.0925) SEATING PLANE 8° 0° 0.33 (0.0130) 0.20 (0.
PAGE 19
Data Sheet ADM2486 NOTES Rev. E | Page 19 of 20 Downloaded from Arrow.com.
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ADM2486 Data Sheet NOTES ©2004–2013 Analog Devices, Inc. All rights reserved. Trademarks and registered trademarks are the property of their respective owners. D04604-0-11/13(E) Rev. E | Page 20 of 20 Downloaded from Arrow.com.