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LT1342

5V RS232 Transceiver with

3V Logic Interface

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FEATURE

The LT

receiver RS232 transceiver. The LT1342 operates from a

5V supply and a 3V logic supply. Receiver outputs can

interface directly to 3V logic circuits. Included on the chip

is a shutdown pin for reducing supply current to near zero.

All receivers and drivers assume high impedance states

during shutdown.

The driver disable function provides additional control of

operating mode. When driver disable is high the charge

pump and drivers turn off. Receivers continue to operate

during driver disable.

New ESD structures on the chip allow the LT1342 to

survive multiple

±10kV strikes, eliminating the need for

costly TransZorbs

The LT1342 is fully compliant with all EIA RS232 specifi-

cations and operates in excess of 120kbaud even driving

heavy capacitive loads.

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ESD Protection Over

±10kV

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3V Logic Interface

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Uses Small Capacitors: 0.1

µF, 0.2µF

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1

µA Supply Current in Shutdown

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Low Power Driver Disable Operating Mode

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Pin Compatible with LT1137A

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CMOS Comparable Low Power: 60mW

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Operates from a 5V Supply and 3V Logic Supply

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Easy PC Layout: Flowthrough Architecture

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Rugged Bipolar Design

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Outputs Assume a High Impedance State When

Off or Powered Down

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Absolutely No Latchup

DESCRIPTIO

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

TransZorb is a registered trademark of General Instruments, GSI.

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Notebook Computers

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Palmtop Computers

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APPLICATI

Output Waveforms

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LT1342 • TA02

APPLICATI

TYPICAL

RECEIVER

OUTPUT

DRIVER

OUTPUT

INPUT

1

2

3

4

5

6

7

8

9

10

11

12

13

14

28

27

26

25

24

23

22

21

20

19

18

17

16

15

DRIVER 1 OUT

RX1 IN

DRIVER 2 OUT

RX2 IN

RX3 IN

RX4 IN

DRIVER 3 OUT

RX5 IN

ON/OFF

DRIVER 1 IN

RX1 OUT

DRIVER 2 IN

RX2 OUT

RX3 OUT

RX4 OUT

DRIVER 3 IN

RX5 OUT

0.1

µF

2

× 0.1µF

2

× 0.1µF

0.1

µF

GND

DRIVER DISABLE

TO LINE

TO 3V LOGIC

LT1342 • TA01

LT1342

NC