Jan 3-07 Rev B

SP232A/233A/30A/32A

© 2007 Sipex Corporation

Figure 1. Typical Circuit using the SP232A.

FEATURES…

The

SP232A/233A/310A/312A devices are a

family of line driver and receiver pairs that meet

the specifications of RS-232 and V.28 serial

protocols. The ESD tolerance has been im-

proved on these devices to over ±2KV for the

Human Body Model. These devices are pin-to-

pin compatible with popular industry standards.

The

SP232A/233A/310A/312A devices

feature10V/µs slew rate, 120Kbps data rate un-

der load, 0.1µF charge pump capacitors, overall

ruggedness for commercial applications, and

increased drive current for longer and more

flexible cable configurations. This family also

features Sipex's BiCMOS design allowing low

power operation without sacrificing perfor-

mance.

The

SP232A/233A/310A/312A devices have

internal charge pump voltage converters which

allow them to operate from a single +5V supply.

The charge pumps will operate with polarized or

non-polarized capacitors ranging from 0.1 to 1µF

and will generate the ±6V needed for the RS-

232 output levels. Both meet all EIA RS-232F

and ITU V.28 specifications.

The SP310A provides identical features as the

SP232A with the addition of a single control

line which simultaneously shuts down the inter-

nal DC/DC converter and puts all transmitter

and receiver outputs into a high impedance

state. The SP312A is identical to the SP310A

with separate tri-state and shutdown control

lines.

THEORY OF OPERATION

The SP232A, SP233A, SP310A and SP312A

devices are made up of three basic circuit blocks –

1)adriver/transmitter,2)areceiverand3)acharge

pump. Each block is described below.

Driver/Transmitter

The drivers are inverting transmitters, which ac-

cept TTL or CMOS inputs and output the RS-232

signals with an inverted sense relative to the input

logic levels. Typically the RS-232output voltage

swing is ±6V. Even under worst case loading

conditions of 3kOhms and 2500pF, the output is

guaranteed to be ±5V, which is consistent with the

RS-232 standard specifications. The transmitter

outputs are protected against infinite short-circuits

to ground without degradation in reliability.

9

8

R IN

R OUT

2

12

13

R IN

R OUT

1

10

7

T IN

2

T OUT

2

11

14

T IN

1

T OUT

1

15

GND

400k

400k

3

1

C +

C -

1

1

6

16

V+

+

+

0.1 F

6.3V

µ

Charge Pump

+5V INPUT

2

V-

2

1

5k

0.1 F

10V

µ

5k

5

4

C +

C -

2

2

+

0.1 F

10V

µ

0.1 F 6.3V

µ

10 F 6.3V

µ

SP232A

+

+

*

*The negative terminal of the V+ storage capacitor can be tied

is recommended.