1

®

FN6046.3

ISL8483, ISL8485, ISL8488,

ISL8489, ISL8490, ISL8491

5V, Low Power, High Speed or Slew Rate

Limited, RS-485/RS-422 Transceivers

The Intersil RS-485/RS-422 devices are BiCMOS 5V

powered, single transceivers that meet both the RS-485 and

RS-422 standards for balanced communication. Unlike

competitive devices, this Intersil family is specified for 10%

tolerance supplies (4.5V to 5.5V).

The ISL8483, ISL8488, and ISL8489 utilize slew rate limited

drivers which reduce EMI, and minimize reflections from

improperly terminated transmission lines, or unterminated

stubs in multidrop and multipoint applications.

Data rates up to 5Mbps are achievable by using the

ISL8485, ISL8490, or ISL8491, which feature higher slew

rates.

All devices present a “single unit load” to the RS-485 bus,

which allows up to 32 transceivers on the network.

Receiver (Rx) inputs feature a “fail-safe if open” design,

which ensures a logic high Rx output if Rx inputs are

floating.

Driver (Tx) outputs are short circuit protected, even for

voltages exceeding the power supply voltage. Additionally,

on-chip thermal shutdown circuitry disables the Tx outputs to

prevent damage if power dissipation becomes excessive.

The ISL8488 - 91 are configured for full duplex (separate Rx

input and Tx output pins) applications. The ISL8488 and

ISL8490 are offered in space saving 8 lead packages for

applications not requiring Rx and Tx output disable functions

(e.g., point-to-point). Half duplex configurations (ISL8483,

ISL8485) multiplex the Rx inputs and Tx outputs to allow

transceivers with Rx and Tx disable functions in 8 lead

packages.

Features

• Specified for 10% Tolerance Supplies

• Class 3 ESD Protection (HBM) on all Pins. . . . . . . . >7kV

• High Data Rates . . . . . . . . . . . . . . . . . . . . . . up to 5Mbps

• Slew Rate Limited Versions for Error Free Data

Transmission at 250kbps (ISL8483, ISL8488, ISL8489)

• Single Unit Load Allows up to 32 Devices on the Bus

• 1nA Low Current Shutdown Mode (ISL8483)

• Low Quiescent Current:

• -7V to +12V Common Mode Input Voltage Range

• Three State Rx and Tx Outputs (Except ISL8488,

ISL8490)

• 30ns Propagation Delays, 5ns Skew (ISL8485, ISL8490,

ISL8491)

• Full Duplex and Half Duplex Pinouts

• Operate from a Single +5V Supply (10% Tolerance)

• Current Limiting and Thermal Shutdown for driver

Overload Protection

Applications

• Factory Automation

• Security Networks

• Building Environmental Control Systems

• Industrial/Process Control Networks

• Level Translators (e.g., RS-232 to RS-422)

• RS-232 “Extension Cords”

TABLE 1. SUMMARY OF FEATURES

PART

NUMBER

HALF/FULL

DUPLEX

NO. OF DEVICES

ALLOWED ON BUS

DATA RATE

(Mbps)

SLEW-RATE

LIMITED?

RECEIVER/

DRIVER ENABLE?

QUIESCENT

LOW POWER

SHUTDOWN?

PIN

COUNT

ISL8483

Half

32

0.25

Yes

Yes

160

Yes

8

ISL8485

Half

32

5

No

Yes

340

No

8

ISL8488

Full

32

0.25

Yes

No

160

No

8

ISL8489

Full

32

0.25

Yes

Yes

160

No

14

ISL8490

Full

32

5

No

No

340

No

8

ISL8491

Full

32

5

No

Yes

340

No

14

Data Sheet

December 2003

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

1-888-INTERSIL or 321-724-7143

Copyright © Intersil Americas Inc. 2003. All Rights Reserved.

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