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LTC1348

3.3V/5V Low Power RS232

3-Driver/5-Receiver Transceiver

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FEATURE

DESCRIPTIO

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Low Supply Current: 600

µA at 3.3V

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Supply Current in Shutdown: 0.2

µA

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Supply Current in Receiver Alive Mode: 15

µA

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ESD Protection over

±10kV

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Operates from a Single 3V to 5.5V Supply

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Operates to 120kBaud with 0.1

µF Flying Capacitors

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Three-State Outputs Are High Impedance When Off

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Output Overvoltage Does Not Force Current

Back into Supplies

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RS232 I/O Lines Can Be Forced to

±25V

Without Damage

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Flowthrough Architecture

The LTC

with very low supply current. The charge pump only

requires five 0.1

µF capacitors. The LTC1348 provides full

RS232 output levels when operated over a wide supply

range of 3V to 5.5V

The transceiver operates in one of four modes: Normal,

Receiver Disable, Receiver Alive and Shutdown. In Normal

800

µA at 5V in the no load condition. In Shutdown mode,

the supply current is further reduced to 0.2

µA. In Receiver

Alive mode, all five receivers are kept alive and the supply

current is 15

µA. All RS232 outputs assume a high imped-

ance state in Shutdown or Receiver Alive mode or with the

power off. The receiver outputs assume a high impedance

state in Receiver Disable or with the power off.

The LTC1348 is fully compliant with all data rate and

overvoltage RS232 specifications. The transceiver oper-

ates up to 120kbaud with all drivers loaded with 1000pF,

3k

Ω.Bothdriveroutputsandreceiverinputscanbeforced

to

±25V without damage and can survive multiple ±10kV

ESD strikes.

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APPLICATI

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Notebook Computers

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Palmtop Computers

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Printers

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Portable Instruments

LT1348 • TA01

C5

0.1

µF

C2

0.1

µF

C3

0.1

µF

C4

0.1

µF

LTC1348

1

2

3

4

5

6

7

8

9

10

11

12

13

14

DR 1 OUT

RX1 IN

DR 2 OUT

RX2 IN

RX3 IN

RX4 IN

DR 3 OUT

RX5 IN

28

27

26

25

24

23

22

21

20

19

18

17

16

15

DR 1 IN

RX1 OUT

DR 2 IN

RX2 OUT

RX3 OUT

RX4 OUT

DR 3 IN

RX5 OUT

DREN

RXEN

GND

C1

0.1

µF

3-Drivers/5-Receivers with Shutdown

APPLICATI

TYPICAL

Supply Current

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

TEMPERATURE (˚C)

–40

1.4

20

LT1348 •TA02

0.8

0.4

–20

0

40

0.2

0

1.6

1.2

1.0

0.6

1.4

0.8

0.4

0.2

0

1.6

1.2

1.0

0.6

60

80

QUIESCENT

CURRENT

SHUTDOWN

CURRENT

OR 5V