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

SP3238E_100_020111

11

Figure 15. Circuit for the connectivity of the SP3238E with a DB-9 connector

6. DCE Ready

7. Request to Send

8. Clear to Send

9. Ring Indicator

DB-9 Connector Pins:

1. Received Line Signal Detector

2. Received Data

3. Transmitted Data

4. Data Terminal Ready

5. Signal Ground (Common)

6

7

8

9

1

2

3

4

5

DB-9

Connector

26

0.1µF

C5

+

GND

2

To µP Supervisor

Circuit

8

9

11

5kΩ

5kΩ

5kΩ

16

21

20

18

5

6

7

10

12

24

23

22

19

17

SP3238E

28

25

3

1

27

4

C3

C4

+

+

C1+

C1-

C2+

C2-

V+

V-

+

C2

C1

+

13

14

15

ONLINE

SHUTDOWN

STATUS

0.1µF

0.1µF

0.1µF

0.1µF