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Exar Corporation 48720 Kato Road, Fremont CA, 94538 • 510-668-7017 • www.exar.com

SP3243E_100_072309

Table 1. Device Pin Description

PIN NUMBER

NAME

FUNCTION

SP3243E

SP3243EUCR

QFN

C1+

Positive terminal of the voltage doubler charge-pump capacitor

28

28

V+

Regulated +5.5V output generated by the charge pump

27

26

C1-

Negative terminal of the voltage doubler charge-pump capacitor

24

22

C2+

Positive terminal of the inverting charge-pump capacitor

1

29

C2-

Negative terminal of the inverting charge-pump capacitor

2

31

V-

Regulated -5.5V output generated by the charge pump

3

32

R

RS-232 receiver input.

4

2

R

RS-232 receiver input

5

3

R

RS-232 receiver input

6

4

R

RS-232 receiver input

7

5

R

RS-232 receiver input

8

6

R

TTL/CMOS receiver output

19

17

R

TTL/CMOS receiver output

18

16

R

Non-inverting receiver-2 output, active in shutdown

20

18

R

TTL/CMOS receiver output

17

15

R

TTL/CMOS receiver output

16

14

R

TTL/CMOS receiver output

15

13

STATUS

TTL/CMOS Output indicating online and shutdown status

21

19

T

TTL/CMOS driver input

14

12

T

TTL/CMOS driver input

13

11

T

TTL/CMOS driver input

12

10

ONLINE

Apply logic HIGH to override AUTO ON-LINE® circuitry

keeping drivers acive (SHUTDOWN must also be logic

HIGH, refer to Table 2)

23

21

T1

OUT

RS-232 driver output

9

7

T2

OUT

RS-232 driver output

10

8

T3

OUT

RS-232 driver output

11

9

GND

Ground

25

23

V

CC

+3.0V to +5.5V supply voltage

26

25

SHUTDOWN Apply logic LOW to SHUTDOWN driver and charge pump.

This overrides all AUTO ON-LINE® circuitry and ONLINE

(Refer to table 2)

22

20

NC

No Connection

-

1,24,27,30