ST3243B ST3243C

Pin configuration

Doc ID 7539 Rev 10

5/17

14

First transmitter input voltage

15

Fifth receiver output voltage

16

Fourth receiver output voltage

17

Third receiver output voltage

18

Second receiver output voltage

19

First receiver output voltage

20

Non-inverting complementary receiver output, always active for wake-up

21

INVALID

Output of the valid signal detector. Indicates if a valid RS-232 level is present

on receiver inputs logic “1”

22

FORCEOFF

Drive low to shut down transmitters and on-board power supply. This

overrides all automatic circuitry and FORCEON

23

FORCEON

Drive high to override automatic circuitry keeping transmitters on

(FORCEOFF must be high)

24

Negative terminal of voltage-charge pump capacitor

25

GND

Ground

26

Supply voltage

27

V+

5.5 V generated by the charge pump

28

Positive terminal of voltage-charge pump capacitor

Table 2.

Pin description (continued)

Pin n°

Symbol

Name and function

Table 3.

Truth table

FORCEOFF

0

HIGH Z

HIGH Z

1.

are present on all receiver input.