+2.35V to +5.5V, 1µA, 2Tx/2Rx RS-232 Transceivers

with ±15kV ESD-Protected I/O and Logic Pins

8

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+0.3V

-0.3V

INVALID

R_IN

INVALID ASSERTED IF ALL RECEIVER INPUTS ARE BETWEEN +0.3V AND -0.3V FOR

AT LEAST 30

µs.

30µs

TIMER

R

+2.7V

-2.7V

INVALID

R_IN

INVALID DEASSERTED IF ANY RECEIVER INPUT HAS BEEN BETWEEN +2.7V AND -2.7V

FOR LESS THAN 30

µs.

0.3

µs

TIMER

R

Figure 2a. INVALID Functional Diagram, INVALID Low

Figure 2b. INVALID Functional Diagram, INVALID High

Table 1. AutoShutdown Plus Truth Table

OPERATION

STATUS

FORCEON

FORCEOFF

VALID

RECEIVER

LEVEL

RECEIVER OR

TRANSMITTER EDGE

WITHIN 30s

T_OUT

R_OUT

Shutdown

(Forced Off)

X

0

X

X

High-Z

Active

Normal Operation

(Forced On)

1

1

X

X

Active

Active

Normal Operation

(AutoShutdown

Plus)

0

1

X

Yes

Active

Active

Shutdown

(AutoShutdown

Plus)

0

1

X

No

High-Z

Active

Normal Operation

INVALID

1

Yes

X

Active

Active

Normal Operation

INVALID

1

X

Yes

Active

Active

Shutdown

INVALID

1

No

No

High-Z

Active

Normal Operation

(AutoShutdown)

INVALID

INVALID

Yes

X

Active

Active

Shutdown

(AutoShutdown)

INVALID

INVALID

No

X

High-Z

Active

X = Don’t care