1

Fault Protected, Extended CMR, RS-485/RS-422

Transceivers with Cable Invert

ISL31480E, ISL31483E, ISL31485E, ISL31486E

The ISL3148xE are fault protected, 5V powered

differential transceivers that exceed the RS-485 and

RS-422 standards for balanced communication. The

RS-485 transceiver pins (driver outputs and receiver

inputs) are protected against faults up to ±60V.

Additionally, the extended common mode range allows

these transceivers to operate in environments with

common mode voltages up to ±25V (>2X the RS-485

requirement), making this RS-485 family one of the

most robust on the market.

Transmitters deliver an exceptional 2.5V (typical)

differential output voltage into the RS-485 specified 54Ω

load. This yields better noise immunity than standard

RS-485 ICs, or allows up to six 120Ω terminations in star

network topologies.

Receiver (Rx) inputs feature a “Full Fail-Safe” design,

which ensures a logic high Rx output if Rx inputs are

floating, shorted, or on a terminated but undriven (idle)

bus.

The ISL31483E, ISL31485E and ISL31486E include cable

invert functions that reverse the polarity of the Rx and/or

Tx bus pins in case the cable is misconnected. Unlike

competing devices, Rx full fail-safe operation is

maintained even when the Rx input polarity is switched.

The ISL31480E and ISL31486E feature a logic supply

switching points of the logic input pins, to be compatible

with a lower supply voltage (down to 1.8V) in mixed

voltage systems. See Table 1 on page 2 for key features

and configurations by device number.

Features

• Fault Protected RS-485 Bus Pins. . . . . . up to ±60V

• Extended Common Mode Range . . . . . . . . . . ±25V

More Than Twice the Range Required for RS-485

• Cable Invert Pins (Except ISL31480)

Corrects for Reversed Cable Connections While

Maintaining Rx Full Fail-safe Functionality

Simplifies Interface to Lower Voltage Logic Devices

• Full Fail-safe (Open, Short, Terminated) RS-485

Receivers

• 1/4 Unit Load (UL) for up to 128 Devices on the Bus

• Hot Plug Circuitry - Tx and Rx Outputs Remain

Three-State During Power-up/Power-down

• Slew Rate Limited RS-485 Data Rate . . . . . . 1Mbps

• Low Quiescent Supply Current . . . . . . . . . . . 2.3mA

Ultra Low Shutdown Supply Current . . . . . . . . 10µA

Applications*(see page 19)

• Utility Meters/Automated Meter Reading Systems

• High Node Count Systems

• PROFIBUS® and Field Bus Networks, and Factory

Automation

• Security Camera Networks

• Building Lighting and Environmental Control Systems

• Industrial/Process Control Networks

Exceptional Rx Operates at

1Mbps Even With ±25V

Common Mode Voltage

Transceivers Deliver Superior

Common Mode Range vs.

Standard RS-485 Devices

-5

0

5

10

15

20

25

30

TIME (400ns/DIV)

B

VID = ±1V

A

RO

ISL3148XE

CLOSEST

COMPETITOR

STANDARD RS-485

TRANSCEIVER

-25

-20

-12

-7

0

12

25

CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.

1-888-INTERSIL or 1-888-468-3774

Copyright Intersil Americas Inc. 2010. All Rights Reserved

All other trademarks mentioned are the property of their respective owners.

June 25, 2010

FN7638.0