3

FN4878.8

February 27, 2006

Pin Descriptions

PIN

FUNCTION

System power supply input (3.0V to 5.5V).

V+

Internally generated positive transmitter supply (+5.5V).

V-

Internally generated negative transmitter supply (-5.5V).

GND

Ground connection.

C1+

External capacitor (voltage doubler) is connected to this lead.

C1-

External capacitor (voltage doubler) is connected to this lead.

C2+

External capacitor (voltage inverter) is connected to this lead.

C2-

External capacitor (voltage inverter) is connected to this lead.

TTL/CMOS compatible transmitter Inputs.

RS-232 level (nominally

±5.5V) transmitter outputs.

RS-232 compatible receiver inputs.

TTL/CMOS level receiver outputs.

TTL/CMOS level, noninverting, always enabled receiver outputs.

INVALID

Active low output that indicates if no valid RS-232 levels are present on any receiver input.

READY

Active high output that indicates when the ICL32XXE is ready to transmit (i.e., V-

≤ -4V)

FORCEOFF Active low to shut down transmitters and on-chip power supply. This overrides any automatic circuitry and FORCEON (see Table 2).

FORCEON

Active high input to override automatic powerdown circuitry thereby keeping transmitters active. (FORCEOFF must be high).

Typical Operating Circuits

ICL3225

19

0.1

µF

+

0.1

µF

+

0.1

µF

13

12

17

8

2

4

3

7

V+

V-

C1+

C1-

C2+

C2-

+

0.1

µF

5

6

16

5k

Ω

9

10

5k

Ω

15

READY

1

GND

+3.3V

+

0.1

µF

18

TTL/CMOS

LOGIC LEVELS

RS-232

LEVELS

FORCEON

FORCEOFF

14

20

11

INVALID

TO POWER

CONTROL LOGIC

ICL3225, ICL3245