Exar Corporation 48720 Kato Road, Fremont CA, 94538 • 50-668-707 • www.exar.com

SP332_00_0260

The

SP332 is a monolithic device that contains both RS-232 and RS-485 line drivers and

receivers. The configuration of the

SP332 can be changed at any time by changing the logic

state of two control pins. The device also includes a loop back function which internally con-

nects driver outputs to receiver inputs for a chip self test. An

Exar-patended charge pump

allows +5V-only operation.

DESCRIPTION

• +5V Only Single Supply Operation

• Software Programmable RS-232 or RS-485

Selection

• 4 Drivers, 4 Receivers RS-232

• 2 Drivers, 2 Receivers RS-485

• Loop back function for Self Test

• 28-pin WSOIC package

SP332

TYPICAL APPLICATIONS CIRCUIT

SEL A

TTL/CMOS

TTL/CMOS

TTL/CMOS

C1+

C1-

C2+

C2-

1

SEL B

2

+5V

VCC

5

GND

8

9

11

12

13

19

20

22

24

26

27

28

TTL/CMOS

TTL/CMOS

TTL/CMOS

TTL/CMOS

T1

T3

R1

RS-485

RS-485

RS-485

V+

V-

RS-485

RS-485

RS-485

4

6

7

10

14

15

16

23

25

3

RI1

RI2

TX3

TX4

TX1

TX2

TI1

TI2

TI3

TI4

RX1

RX2

TTL/CMOS

21

R3

17

18

RI4

RI3

RX3

RX4

15KΩ

400KΩ

Vcc

400KΩ

Vcc

RS-485

RS-485

+5V

+5V

+5V

GND

TTL/CMOS

TTL/CMOS

TTL/CMOS

TTL/CMOS

0.1µF

VCC

V+

V-

SHUTDOWN

RS-232

TTL/CMOS

TTL/CMOS

TTL/CMOS

TTL/CMOS

T1

T2

T3

T4

TX1

TX2

TX3

TX4

TI1

TI2

TI3

TI4

RI1

RI2

RI3

RI4

RX1

RX2

RX3

RX4

1

3

4

5

6

7

8

10

C1+

C1-

C2+

C2-

9

11

12

13

14

15

16

17

18

19

20

21

22

23

SEL B

2

SEL A

24

25

26

27

28

R1

R2

R3

R4

5KΩ

400KΩ

Vcc

Vcc

Vcc

Vcc

RS-232

RS-232

RS-232

RS-232

RS-232

RS-232

RS-232

LOOPBACK

0V

0V

SP332

SP332

0.1µF

0.1µF

0.1µF

400KΩ

400KΩ

400KΩ

5KΩ

5KΩ

5KΩ

0.1µF

0.1µF

0.1µF

0.1µF

15KΩ

15KΩ

15KΩ

TTL/CMOS

SHUTDOWN

LOOPBACK

TTL/CMOS

TTL/CMOS

RS-232 Mode

Full Duplex RS-485 Mode

TTL/CMOS

RS-232/RS-485 Multi-mode SerialTransceiver

TI4

SEL_B

TX4

TX3

VCC

TX1

TX2

GND

C1+

V+

C2+

C1–

C2–

V–

TI3

TI2

TI1

SD

SEL_A

LB

RX4

RX3

RX2

RX1

RI4

RI3

RI2

RI1

28

27

26

25

24

23

22

21

20

19

18

17

16

15

1

2

3

4

5

6

7

8

9

10

11

12

13

14