_______________________________________________________________________________________

5

______________________________________________________________Pin Description

TTL/CMOS Receiver Outputs

FUNCTION

PIN

NAME

1

3

7

8

9

10

11, 12

14

15

R2OUT

16

17

18

Invalid Signal Detector Output, active low. A logic high indicates that a valid RS-232

level is present on a receiver.

T2N

TTL/CMOS Transmitter Outputs

2

INVALID

5

T1OUT

RS-232 Transmitter Outputs

FORCEON

Force-On Input, active high. Drive high to override AutoShutdown Plus, keeping

transmitters and receivers active (FORCEOFF must be high) (Table 1).

13

R1IN

RS-232 Receiver Outputs

C1+

Positive terminal of the internal voltage-doubling charge-pump capacitor. Leave

unconnected or connect to an external 0.1µF capacitor. See

Charge Pump Section.

Supply Voltage (MAX3233E = +3.3V, MAX3235E = +5.0V)

FORCEOFF

Force-Off Input, active low. Drive low to shut down transmitters, receivers, and charge

pump. This overrides AutoShutdown Plus and FORCEON (Table 1).

V+

+5.5V generated by the charge pump. Do not connect.

C1-

Negative terminal of the internal voltage-doubling charge-pump capacitor. Leave

unconnected or connect to an external 0.1µF capacitor. See

Charge Pump Section.

C2+

Positive terminal of the internal inverting charge-pump capacitor. Do not connect.

C2-

Negative terminal of the internal inverting charge-pump capacitor. Do not connect.

V-

-5.5V generated by the charge pump. Do not connect.

GND

Ground

±15kV ESD-Protected, 1µA, 250kbps, 3.3V/5V, Dual

RS-232 Transceivers with Internal Capacitors

6

R1OUT

4

T1IN

19

T2OUT

20

R2IN