5

LTC1337

1337fa

PI FU CTIO S

DRIVER IN: RS232 Driver Input Pins. Inputs are TTL/

CMOS compatible. Inputs should not be allowed to float.

DRIVER OUT: Driver Outputs at RS232 Voltage Levels.

Outputs are in a high impedance state when in Shutdown

ESD to ±10kV for human body model discharges.

RX IN: Receiver Inputs. These pins can be forced to ±25V

without damage. The receiver inputs are protected against

ESD to ±10kV for human body model discharges. Each

receiver provides 0.4V of hysteresis for noise immunity.

RX OUT: Receiver Outputs with TTL/CMOS Voltage Levels.

Outputs are in a high impedance state when in Shutdown

mode to allow data line sharing.

TEST CIRCUITS

DRIVER

DRIVER

INPUT

3k

51pF

DRIVER

OUTPUT

1337 F03

Figure 3. Driver Timing Test Load

ESD Test Circuit

1337 TC01

C1

0.1µF

LTC1337

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

28

27

26

25

24

23

22

21

20

19

18

17

16

15

C3

0.1µF

DRIVER 1 IN

RX1 OUT

DRIVER 2 IN

RX2 OUT

RX3 OUT

RX4 OUT

DRIVER 3 IN

RX5 OUT

C2

0.1µF

C4

0.1µF

GND

RS232

LINE PINS

PROTECTED

TO ±10kV

RX

RX IN

51pF

RX

OUTPUT

1337 F04

Figure 4. Receiver Timing Test Load

Figure 1. Driver Propagation Delay Timing

0.8V

0V

0V

RX IN

RX

OUTPUT

1.3V

1.7V

1337 F02

0V

Figure 2. Receiver Propagation Delay Timing

SWITCHI G TI E WAVEFOR S

1.4V

0V

0V

0V

DRIVER

INPUT

DRIVER

OUTPUT

1.4V

1337 F01