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LT1780/LT1781

Low Power 5V RS232

Dual Driver/Receiver with

±15kV ESD Protection

TransZorb is a registered trademark of General Instruments, GSI.

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Output Waveforms

1780/81 • TA02

DRIVER

OUTPUT

RECEIVER

OUTPUT

INPUT

0.1

µF

0.1

µF

0.1

µF

0.1

µF

LOGIC

INPUTS

LOGIC

OUTPUTS

ON/OFF

18

10

13

11

12

6

5

4

2

16

9

14

8

15

7

3

17

5V INPUT

RS232 OUTPUT

RS232 OUTPUT

RS232 INPUT

RS232 INPUT

1780/81 • TA01

5k

5k

LT1780

APPLICATI

TYPICAL

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FEATURE

DESCRIPTIO

The LT

with integral charge pump to generate RS232 voltage

levels from a single 5V supply. Using only 0.1

µF external

capacitors, these circuits consume only 40mW of power,

and can operate to 120kbaud even while driving heavy

capacitive loads. New ESD structures on the chip allow the

LT1780/LT1781 to survive

±15kV air gap and ±8kV con-

tact ESD tests per IEC 1000-4-2, eliminating the need for

costly TransZorbs

LT1781 are fully compliant with EIA RS232 standards.

Driver outputs are protected from overload, and can be

shorted to ground or up to

±30V without damage. During

SHUTDOWN or power-off conditions, driver and receiver

outputs are in a high impedance state, allowing line

sharing.

The LT1780/LT1781 are direct upgrades to the LT1180A/

LT1181A, LT1280A/LT1281A and LT1381 for applications

which require the utmost ESD protection.

The LT1781 is available in 16-pin DIP,SO and SW pack-

ages. The LT1780 is supplied in 18-pin DIP and SW

packages for applications which require SHUTDOWN.

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10mA Max Supply Current

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ESD Protection to IEC 1000-4-2 Level 4

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Uses Small Capacitors: 0.1

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Outputs Withstand

±30V Without Damage

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CMOS Comparable Low Power: 40mW

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Operates from a Single 5V Supply

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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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Meets All RS232 Specifications

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Available With or Without Shutdown

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Absolutely No Latch-up

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Portable Computers

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Battery-Powered Systems

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Power Supply Generator

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Terminals

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Modems

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APPLICATI

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