3V to 5.5V, up to 250kbps True RS-232 Transceiver

with 4µA AutoShutdown Plus and Power-On Reset

_______________________________________________________________________________________

5

______________________________________________________________Pin Description

300

0

10

100

1000

MAXIMUM TRANSIENT DURATION

vs. RESET COMPARATOR OVERDRIVE

50

RESET COMPARATOR OVERDRIVE (mV)

100

200

150

250

NOT IN

SHUTDOWN

MODE

SHUTDOWN MODE

0.960

0.970

1.010

1.000

0.990

0.980

1.030

1.020

1.040

-40

0

-20

20

40

80

60

NORMALIZED POWER-UP RESET

DELAY vs. TEMPERATURE

TEMPERATURE (°C)

____________________________Typical Operating Characteristics (continued)

otherwise noted.)

20

C1+

Positive terminal of voltage-doubler charge-pump capacitor

19

+3V to +5.5V Supply Voltage

18

C1-

Negative terminal of voltage-doubler charge-pump capacitor

NAME

FUNCTION

1

V+

5.5V generated by the charge pump

2

C2+

Positive terminal of inverting charge-pump capacitor

PIN

3

C2-

Negative terminal of inverting charge-pump capacitor

4

V-

-5.5V generated by the charge pump

10

RESET

9

INVALID

Output of the Valid Signal Detector. Asserts when no valid RS-232 levels are present on any of

the receiver inputs for 90µs.

7, 8

R_OUT

TTL/CMOS Receiver Outputs (R1OUT and R2OUT)

5, 6

T_IN

TTL/CMOS Transmitter Inputs (T1IN and T2IN)

17

GND

Ground

15, 16

T_OUT

RS-232 Transmitter Outputs (T2OUT and T1OUT)

13, 14

R_IN

RS-232 Receiver Inputs (R2IN and R1IN)

12

FORCEON

Force-On Input. Drive FORCEON high to override AutoShutdown Plus, keeping transmitters on

(FORCEOFF must be high) (Table 1).

11

FORCEOFF

Force-Off Input. Drive FORCEOFF low to shut down transmitters and on-board power supply.

This overrides AutoShutdown Plus and FORCEON (Table 1).