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LTC1480

3.3V Ultra-Low Power

RS485 Transceiver

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FEATURE

DESCRIPTIO

The LTC

ceiver which provides full RS485 compatibility while oper-

ating from a single 3.3V supply. It is designed for data

transmission standard RS485 applications with extended

common-mode range (12V to –7V). It also meets the

requirements of RS422 and features high speed operation

up to 2.5Mb/s. The CMOS design offers significant power

savings without sacrificing ruggedness against overload

or ESD damage. Typical quiescent current is only 300

µA

while operating and 1

µA in shutdown.

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. I/O pins are protected against multiple

ESD strikes of up to

±10kV.

The LTC1480 is fully specified over the commercial and

extended industrial temperature range. The LTC1480 is

available in 8-pin SO and DIP packages.

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True RS485 from a Single 3.3V Supply

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1

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ESD Protection to

Driver Outputs

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–7V to 12V Common-Mode Range Permits

±7V

Ground Difference Between Devices on the Data Line

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Thermal Shutdown Protection

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Power Up/Down Glitch-Free Driver Outputs Permit

Live Insertion or Removal of Transceiver

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Driver Maintains High Impedance in Three-State or

with the Power Off

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Up to 32 Transceivers on the Bus

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50ns Typical Driver Propagation Delays with

10ns Skew

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Pin Compatible with the LTC485

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

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Battery-Powered RS485/RS422 Applications

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Low Power RS485/RS422 Transceiver

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Level Translator

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APPLICATI

APPLICATI

TYPICAL

Driver Differential

Output Voltage vs Output Current

3.3V RS485 Network

RO

RE

DE

D1

1

2

3

4

8

7

6

5

LTC1480 • TA01

LTC1480

LTC1480

A

A

B

B

A

B

120

Ω

120

Ω

SHIELD

SHIELD

R

D

3.3V

RO

RE

DE

D1

1

2

3

4

8

7

6

5

LTC1480

R

D

3.3V

3.3V

R

D

1234

8765

RO

RE

DE D1

OUTPUT CURRENT (mA)

0

0

0.5

1.0

1.5

2.0

2.5

60

70

80

LTC1480 • TA02

10

20

30

40

50

90

3.0

3.5