Pin configuration

ST3243

4/20

1.1

Truth table

Note:

If the part is in auto-powerdown mode (FORCE OFF = VCC, FORCE ON = GND) it is

shutdown, if no valid RS-232 levels are present on all receiver input

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 over-

rides 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+

5.5V Generated by the charge pump

28

Positive terminal of voltage-charge pump capacitor

Table 1.

Pin description

Pin n°

Symbol

Name and function

Table 2.

FORCE OFF

0

HIGH Z

HIGH Z

ACTIVE Note:

1

ACTIVE Note:

ACTIVE Note:

ACTIVE Note: