1

LTC1334

Single 5V RS232/RS485

Multiprotocol Transceiver

The LTC

ceiver featuring two reconfigurable interface ports. It can

be configured as two RS485 differential ports, as two dual

RS232 single-ended ports or as one RS485 differential

port and one dual RS232 single-ended port. An onboard

charge pump requires four 0.1

µF capacitors to generate

boosted positive and negative supplies, allowing the RS232

drivers to meet the RS232

±5V output swing requirement

with only a single 5V supply. A shutdown mode reduces

The RS232 transceivers are in full compliance with RS232

specifications. The RS485 transceivers are in full compli-

ance with RS485 and RS422 specifications. All interface

drivers feature short-circuit and thermal shutdown pro-

tection. An enable pin allows RS485 driver outputs to be

forced into high impedance, which is maintained 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 allows the driver

outputs to be connected back to the receiver inputs for

diagnostic self-test.

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Four RS232 Transceivers or Two RS485

Transceivers on One Chip

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Operates from a Single 5V Supply

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Withstands Repeated

±10kV ESD Pulses

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Uses Small Charge Pump Capacitors: 0.1

µF

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Low Supply Current: 8mA Typical

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10

µA Supply Current in Shutdown

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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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Receiver Inputs Can Withstand

±25V

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Low Power RS485/RS422/RS232/EIA562 Interface

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Software-Selectable Multiprotocol Interface Port

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Cable Repeaters

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Level Translators

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

21

5V

8

5V

9

5V

20

0V

26

3

26

3

27

28

5V

120

Ω

4

LTC1334

LTC1334 • TA01

RX OUT

23

RS485 INTERFACE

DR ENABLE

5

6

7

14

24

DR IN

22

15

13

21

LTC1334

RX OUT

18

5V

DR ENABLE

12

11

10

9

8

14

17

DR IN

19

5V

20

15

120

Ω

4000-FT 24-GAUGE TWISTED PAIR

5V

0V

11

DR IN

19

4

24

RX OUT

12

16

RX OUT

7

DR IN

23

RS232 INTERFACE

ALL CAPACITORS: 0.1

µF MONOLITHIC CERAMIC TYPE

10

DR IN

18

5

25

RX OUT

13

17

RX OUT

6

DR IN

22

1

2

2

1

28

27

5V

DESCRIPTIO

FEATURES

APPLICATIO S

TYPICAL APPLICATIO