REV Pr. B

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 rights of third parties

which may result from its use. No license is granted by implication or

otherwise under any patent or patent rights of Analog Devices.

a

+5 V Low Power

RS-485PROFIBUSTransceiver

FUNCTIONAL BLOCK DIAGRAM

FEATURES

Meets & Exceeds EIA RS-485 & EIA RS-422 Standard

50 Mb/s Data Rate

Recommended for PROFIBUS Applications

2.1V Minimum Differential Output with 54

Termination

Thermal Shutdown & Short Circuit Protection

Zero Skew Driver & Receiver

Driver Propagation Delay: 8 ns

Receiver Propagation Delay: 12 ns

High Z Outputs with Drivers Disabled or Power Off

Superior Upgrade for SN65ALS1176

15kV HBM ESD Protection on I/O Pins A & B

Available in Standard 8-pin SOIC & Miniature 8-pin

Micro SOIC packages

APPLICATIONS

Industrial Field Equipment

One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.

Tel: 781/329-4700

World Wide Web Site: http://www.analog.com

Fax: 781/326-8703

© Analog Devices, Inc., 2000

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ADM1486

GENERAL DESCRIPTION

The ADM1486 is a differential line transceiver suitable

for high speed bidirectional data communication on

multipoint bus transmission lines. It is designed for

balanced data transmission, complies with EIA Standards

RS-485 and RS-422 and is recommended for PROFIBUS

applications. The part contains a differential line driver

and a differential line receiver. Both the driver and the

receiver may be enabled independently. When disabled or

with power off, the driver outputs are tristated.

The ADM1486 operates from a single +5 V power supply.

Excessive power dissipation caused by bus contention or

by output shorting is prevented by a thermal shutdown

circuit. This feature forces the driver output into a high

impedance state if during fault conditions a significant

temperature increase is detected in the internal driver

circuitry.

Up to 50 transceivers may be connected simultaneously on

a bus, but only one driver should be enabled at any time.

It is important therefore that the remaining disabled

drivers do not load the bus. To ensure this, the ADM1486

driver features high output impedance when disabled and

also when powered down.

This minimizes the loading effect when the transceiver is

not being utilized. The high impedance driver output is

maintained over the entire common-mode voltage range

from –7 V to +12 V.

The receiver contains a fail safe feature which results in a

logic high output state if the inputs are unconnected

(floating).

The ADM1486 is fabricated on BiCMOS, an advanced

mixed technology process combining low power CMOS

with fast switching bipolar technology. All inputs and

outputs contain protection against ESD; all driver outputs

feature high source and sink current capability. An epi-

taxial layer is used to guard against latch-up.

The ADM1486 features extremely fast switching speeds.

Minimal driver propagation delays permit transmission at

data rates up to 50 Mbits/s while low skew minimizes

EMI interference.

The part is fully specified over the commercial and indus-

trial temperature range and is available in an 8-lead

DIL/SOIC/µSOIC package.

Preliminary Technical Data

ADM1486

PRELIMINARY TECHNICAL DATA