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LTC1482

Low Power RS485 Transceiver

with Carrier Detect and

Receiver Fail-Safe

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No Damage or Latchup to

Model), IEC1000-4-2 Level 4 (

Level 3 (

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Active Low Carrier Detect Output

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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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Maximum Data Rate of 4Mbps

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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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Available in 8-Lead MSOP, PDIP and SO Packages

The LTC

ceiver that offers an active low carrier detect output. The

open-drain carrier detect pin allows several transceivers

to share the same carrier detect line and can be used to

detect the insertion or removal of a driven RS485/RS422

cable.

Enhanced ESD protection allows the LTC1482 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 LTC1482 receiver stays alive at all times except in

shutdown. The supply current is a maximum of 700

µA

and 900

µA when the driver is disabled and enabled

respectively. In shutdown, the quiescent current of the

LTC1482 drops to a maximum of 20

µA.

When the driver is disabled or the LTC1482 is in shut-

down, the driver outputs are three-stated and remain in

a high impedance state over the RS485 common mode

range.

Excessive power dissipation caused by bus contention or

faults is prevented by a thermal shutdown circuit, which

forces the driver outputs into a high impedance state.

The LTC1482 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

CD1

DE1

DI1/SHDN1

R

LTC1482

GND1

B1

A1

B2

A2

120

Ω

120

Ω

D

GND2

1482 TA01

R

D

RO2

CD2

DE2

DI2/SHDN2

LTC1482

RS485 Interface

APPLICATIO S

FEATURES

TYPICAL APPLICATIO

DESCRIPTIO

Carrier Detect Output (2000 Foot STP Cable)

DE1

↑↓

1482 TA01a

DE2 = 0

1k PULL-UP AT CD

DE1

A2

B2

CD2