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LTC1484

Low Power

RS485 Transceiver

with Receiver Fail-Safe

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No Damage or Latchup to

Body Model), IEC-1000-4-2 Level 4 Contact (

and Level 3 (

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Guaranteed High Receiver Output State for Floating,

Shorted or Terminated Inputs with No Signal

Present

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Drives Low Cost Residential Telephone Wires

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20

µA Max Quiescent Current in Shutdown Mode

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Single 5V Supply

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– 7V to 12V Common Mode Range Permits

±7V

Ground Difference Between Devices on the Data Line

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Power Up/Down Glitch-Free Driver Outputs

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Up to 32 Transceivers on the Bus

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Pin Compatible with the LTC485

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Available in 8-Lead MSOP, PDIP and SO Packages

The LTC

ceiver. In receiver mode, it offers a fail-safe feature which

guarantees a high receiver output state when the inputs

are left open, shorted together or terminated with no

signal present. No external components are required to

ensure the high receiver output state.

Both driver and receiver feature three-state outputs with

separate receiver and driver control pins. The driver

outputs maintain high impedance over the entire com-

mon mode range when three-stated. Excessive power

dissipation caused by bus contention or faults is pre-

vented by a thermal shutdown circuit that forces the

driver outputs into a high impedance state.

Enhanced ESD protection allows the LTC1484 to with-

stand

±15kV (human body model), IEC-1000-4-2 level 4

(

±8kV) contact and level 3 (±8kV) air discharge ESD

without latchup or damage.

The LTC1484 is fully specified over the commercial and

industrial temperature ranges and is available in 8-lead

MSOP, PDIP and SO packages.

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Battery-Powered RS485/RS422 Applications

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Low Power RS485/RS422 Transceiver

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Level Translator

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

RO1

RE1

DE1

DI1

R

LTC1484

GND1

B1

A1

B2

A2

120

Ω

120

Ω

D

GND2

1484 TA01

R

D

RO2

RE2

DE2

DI2

LTC1484

RS485 Interface

APPLICATIO S

FEATURES

TYPICAL APPLICATIO

DESCRIPTIO

Driving a 2000 Foot STP Cable

Dl1

↑↓

1484 TA01a

Dl2 = 0

DE2 = 0

RE1 = RE2 = 0

Dl1

B2

A2

RO2