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LTC1321/LTC1322/LTC1335

RS232/EIA562/RS485

Transceivers

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FEATURE

The LTC1321/LTC1322/LTC1335 are low power CMOS

bidirectional transceivers, each featuring two reconfigurable

interface ports. Each can be configured as two RS485

differential ports, as two single-ended ports, or as one

RS485 differential port and one single-ended port. The

LTC1321/LTC1322 can provide RS232 or EIA562 compat-

ible single-ended outputs; the LTC1335 provides EIA562

compatible outputs and additionally includes an output

enable pin, allowing the receiver logic level outputs to be

three-stated.

The RS232/EIA562 transceivers operate to 120kbaud and

are in full compliance with EIA/TIA-562 specification. The

RS485 transceivers operate to 10Mbaud and are in full

compliance with RS485 and RS422 specifications. All

interface drivers feature short-circuit and thermal shut-

down protection. An enable pin allows RS485 driver

outputs to be forced into high impedance which is main-

tained even when the outputs are forced beyond supply

rails or power is off. Both driver outputs and receiver

inputs feature

±10kV ESD protection. A loopback mode

connects the driver outputs back to the receiver inputs for

diagnostic self-test.

The LTC1321/LTC1322 can support RS232 voltage levels

when 6.5V

LTC1335 supports receiver output enable but not RS232

to 15

µA.

DESCRIPTIO

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Low Power RS485/RS422/EIA562/RS232 Interface

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Cable Repeater

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Level Translator

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LTC1321: 2-EIA562/RS232 Transceivers/2-RS485

Transceivers

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LTC1322: 4-EIA562/RS232 Transceivers/2-RS485

Transceivers

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LTC1335: 4-EIA562 Transceivers/2-RS485

Transceivers with OE

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LTC1321/LTC1322 Have the Same Pinout as

SP301/SP302

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LTC1335 Features Receiver Three-State Outputs

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Low Supply Current: 1mA Typical

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15

µA Supply Current in Shutdown

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120kBaud in EIA/TIA-562 or RS232 Mode

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10MBaud in RS485/RS422 Mode

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Self-Testing Capability in Loopback Mode

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Power-Up/Down Glitch-Free Outputs

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Driver Maintains High Impedance in Three-State,

Shutdown or With Power Off

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Thermal Shutdown Protection

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I/O Lines Can Withstand

±25V

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Withstands Repeated 10kV ESD Pulses

APPLICATI

TYPICAL

19

5V

6

5V

7

5V

18

0V

1

24

5V

1

24

5V

120

Ω

2

LTC1322

1321/22/35 TA01

RX OUT

21

RS485 INTERFACE

DR ENABLE

3

4

5

12

22

DR IN

20

13

–5V

11

19

LTC1322

RX OUT

16

5V

DR ENABLE

10

9

8

7

6

12

15

DR IN

17

5V

18

13

–5V

120

Ω

4000-FT 24-GAUGE TWISTED PAIR

5V

0V

8

DR IN

17

3

22

RX OUT

11

14

RX OUT

4

DR IN

21

EIA562 INTERFACE

9

DR IN

16

2

23

RX OUT

10

15

RX OUT

5

DR IN

20