1

LTC1349

5V Low Power RS232

3-Driver/5-Receiver Transceiver

with 2 Receivers Active

in SHUTDOWN

APPLICATI

TYPICAL

Quiescent and SHUTDOWN Supply Current

vs Temperature

S

FEATURE

DESCRIPTIO

s

Low Supply Current: 300

µA

s

Two Receivers Kept Alive in SHUTDOWN

s

ESD Protection Over

±10kV

s

Operates from a Single 5V Supply

s

Uses Small Capacitors: 0.1

µF

s

Operates to 120k Baud

s

Three-State Outputs Are High Impedance When Off

s

Output Overvoltage Does Not Force Current

Back into Supplies

s

RS232 I/O Lines Can Be Forced to

±25V

Without Damage

s

Pin Compatible with LT1137A and LT1237

s

Flowthrough Architecture

The LTC1349 is a 3-driver/ 5-receiver RS232 transceiver

with very low supply current. In the no load condition, the

supply current is only 300

µA. The charge pump only

requires four 0.1

µF capacitors.

In SHUTDOWN mode, two receivers are kept alive and the

supply current is 35

µA. All RS232 outputs assume a high

impedance state in SHUTDOWN and with the power off.

The LTC1349 is fully compliant with all data rate and

overvoltage RS232 specifications. The transceiver can

operate up to 120k baud with a 2500pF, 3k

Ω load. Both

driver outputs and receiver inputs can be forced to

±25V

without damage, and can survive multiple

±10kV ESD

strikes.

S

APPLICATI

s

Notebook Computers

s

Palmtop Computers

TEMPERATURE (°C)

1200

1000

800

600

400

200

0

20

40

60

LTC1349 • TA02

80

0

–40

60

50

40

30

20

10

0

QUIESCENT

CURRENT

SHUTDOWN

CURRENT

TEST CONDITION:

–20

100

3-Drivers/5-Receivers with SHUTDOWN

LTC1349 • TA01

C1

0.1

µF

LTC1349

1

2

3

4

5

6

7

8

9

10

11

12

13

14

DRIVER 1 OUT

RX1 IN

DRIVER 2 OUT

RX2 IN

RX3 IN

RX4 IN

DRIVER 3 OUT

RX5 IN

ON/OFF

NC

28

27

26

25

24

23

22

21

20

19

18

17

16

15

C3

0.1

µF

DRIVER 1 IN

RX1 OUT

DRIVER 2 IN

RX2 OUT

RX3 OUT

RX4 OUT

DRIVER 3 IN

RX5 OUT

GND

NC

NC

C2

0.1

µF

C4

0.1

µF