SN75196

MULTIPLE RS-232 DRIVERS AND RECEIVERS

SLLS188B – MAY 1995 – REVISED APRIL 1998

11

POST OFFICE BOX 655303

• DALLAS, TEXAS 75265

APPLICATION INFORMATION

Diodes placed in series with the VDD and VSS terminals protect the SN75196 in the fault condition when the device

outputs are shorted to VDD or VSS and the power supplies are at low and provide low-impedance paths to ground

(see Figure 15).

VDD

VSS

±15 V

Output

VDD

VSS

SN75196

SN75196

Figure 15. Power-Supply Protection to Meet Power-Off Fault Conditions of TIA/EIA-232-F

SN75196

5 V

TL16C450

ACE

1

5

6

9

12 V

–12 V

TIA/EIA-232-F

DB9S

Connector

C2†

C5†

† See Figure 10 to select the correct values for the loading capacitors (C1, C2, C3, C4, and C5), which may be required to meet the RS-232

maximum slew-rate requirement of 30 V/

µs. The value of the loading capacitors required depends upon the line length and desired slew rate,

but is typically 330 pF.

NOTE A: To use the receivers only, VDD and VSS must both be powered or tied to ground.

C4†

C3†

C1†

RI

DTR

CTS

SO

RTS

SI

DSR

DCD

43

37

40

13

36

11

41

42

10

9

8

7

6

5

4

3

2

1

GND

5DA

3RY

4DA

2RY

1RY

2DA

1DA

VCC

3DA

VSS

5DY

3RA

4DY

2RA

1RA

2DY

1DY

VDD

3DY

11

12

13

14

15

16

17

18

19

20

RI

DTR

CTS

TX

RTS

RX

DSR

DCD

Figure 16. Typical TIA/EIA-232-F Connection