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LTC491

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Designed for RS485 or RS422 Applications

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Single +5V Supply

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–7V to +12V Bus Common Mode Range

Permits

±7V Ground Difference Between Devices

on the Bus

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Thermal Shutdown Protection

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Power-Up/Down Glitch-Free Driver Outputs Permit

Live Insertion or Removal of Package

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Driver Maintains High Impedance in Three-State or

with the Power Off

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Combined Impedance of a Driver Output and

Receiver Allows up to 32 Transceivers on the Bus

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70mV Typical Input Hysteresis

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28ns Typical Driver Propagation Delays with 5ns

Skew

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Pin Compatible with the SN75180

Differential Driver and

Receiver Pair

DESCRIPTIO

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FEATURE

The LTC491 is a low power differential bus/line transceiver

designed for multipoint data transmission standard RS485

applications with extended common mode range (+12V to

–7V). It also meets the requirements of RS422.

The CMOS design offers significant power savings over its

bipolar counterpart without sacrificing ruggedness against

overload or ESD damage.

The driver and receiver feature three-state outputs, with

the driver outputs maintaining high impedance over the

entire 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 receiver has a fail safe feature which guarantees a high

output state when the inputs are left open.

Both AC and DC specifications are guaranteed from 0

°C to

70

°C and 4.75V to 5.25V supply voltage range.

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Low Power RS485/RS422 Transceiver

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Level Translator

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APPLICATI

APPLICATI

TYPICAL

LTC491 • TA01

120

Ω

120

Ω

120

Ω

120

Ω

4000 FT 24 GAUGE TWISTED PAIR

4000 FT 24 GAUGE TWISTED PAIR

RECEIVER

LTC491

DRIVER

RECEIVER

LTC491

DRIVER

R

D

R

D

5

2

11

12

10

9

4

DE

3

REB

DE

REB