LTC2859/LTC2861

1

285961fb

20Mbps RS485 Transceivers

with Integrated Switchable

Termination

RS485/422 transceivers operating on 5V supplies. The

receiver includes a logic-selectable 120Ω termination,

one-eighth unit load supporting up to 256 nodes per bus,

and a failsafe feature that guarantees a high output state

under conditions of floating or shorted inputs.

The driver features a logic-selectable low-EMI 250kbps

operating mode, and maintains a high output impedance

over the entire common mode range when disabled or

when the supply is removed. Excessive power dissipation

caused by bus contention or a fault is prevented by current

limiting all outputs and by a thermal shutdown.

Enhanced ESD protection allows the LTC2859 and LTC2861

to withstand ±15kV (human body model) on the transceiver

interface pins without latchup or damage.

■

Low Power RS485/RS422 Transceiver

■

Level Translator

■

Backplane Transceiver

■

Integrated, Logic-Selectable 120Ω Termination

Resistor

■

20Mbps Max Data Rate

■

No Damage or Latchup to ESD: ±15kV HBM

■

High Input Impedance Supports 256 Nodes

■

250kbps Low-EMI Mode

■

Guaranteed Failsafe Receiver Operation Over the

Entire Common Mode Range

■

Current Limited Drivers and Thermal Shutdown

■

Delayed Micropower Shutdown (5μA Max)

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Power Up/Down Glitch-Free Driver Outputs

■

Low Operating Current (900μA Max in Receive Mode)

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Meets All TIA/EIA-485-A Specifications

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Available in 10-Pin 3mm × 3mm DFN, 12-Pin

4mm × 3mm DFN and 16-Pin SSOP Packages

LTC2859 at 20Mbps

PART NUMBER

DUPLEX

PACKAGE

LTC2859

Half

DFN-10

LTC2861

Full

SSOP-16, DFN-12

TYPICAL APPLICATION

FEATURES

APPLICATIONS

DESCRIPTION

PRODUCT SELECTION GUIDE

L, LT, LTC and LTM are registered trademarks of Linear Technology Corporation.

All other trademarks are the property of their respective owners.

285961 TA02

20ns/DIV

2V/DIV

DI

Y–Z

Y

Z

RE

TE

RO

DE

DI

SLO

R

D

2859/61 TA01

LTC2859

120Ω

RE

RO

TE

DE

DI

SLO

R

D

LTC2859

120Ω

RE

RO

TE DE

DI

SLO

R

D

LTC2859

120Ω