FN6046 Rev 10.02

Page 1 of 15

Oct 2, 2023

© 2003-2023 Renesas Electronics

ISL8485, ISL8490, ISL8491

5V, Low Power, High Speed, RS-485/RS-422 Transceivers

DATASHEET

The ISL8485, ISL8490, and ISL8491 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 family is

specified for 10% tolerance supplies (4.5V to 5.5V).

The ISL8485, ISL8490, and ISL8491 feature data rates up to

5Mbps.

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

which allows up to 32 transceivers on the network.

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

which ensures a logic high Rx output if the Rx inputs are

floating.

The 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 ISL8490 and ISL8491 are configured for full duplex

(separate Rx input and Tx output pins) applications. Half

duplex configurations (ISL8485) multiplex the Rx inputs and

Tx outputs to allow transceivers with Rx and Tx disable

functions in 8 Ld packages.

Features

• Specified for 10% tolerance supplies

• Class 3 ESD protection (HBM) on all pins: 7kV

• High data rates: up to 5Mbps

• Single unit load allows up to 32 devices on the bus

• Low quiescent current: 500µA

• -7V to +12V common-mode input voltage range

• Three state Rx and Tx outputs (except ISL8490)

• 30ns propagation delays, 5ns skew

• Full duplex and half duplex pinouts

• Operation from a single +5V supply (10% tolerance)

• Current limiting and thermal shutdown for driver overload

protection

• Pb-free plus anneal (RoHS compliant)

Applications

• Factory automation

• Security networks

• Building environmental control systems

• Industrial/process control networks

• Level translators (for example, RS-232 to RS-422)

• RS-232 “extension cords”