By connecting FORCEON to

INVALID, the MAX3224–

MAX3227/MAX3244/MAX3245 shut down when no valid

receiver level and no receiver or transmitter edge is

detected for 30sec, and wake up when a valid receiver

level or receiver or transmitter edge is detected.

By connecting FORCEON and

FORCEOFF to INVALID,

the MAX3224–MAX3227/MAX3244/MAX3245 shutdown

when no valid receiver level is detected and wake up

when a valid receiver level is detected (same function-

ality as AutoShutdown feature on MAX3221/MAX3223/

MAX3243).

A mouse or other system with AutoShutdown Plus may

need time to wake up. Figure 5 shows a circuit that

forces the transmitters on for 100ms, allowing enough

time for the other system to realize that the MAX3244/

MAX3245 is awake. If the other system outputs valid

RS-232 signal transitions within that time, the RS-232

ports on both systems remain enabled.

1µA Supply Current, 1Mbps, 3.0V to 5.5V,

RS-232 Transceivers with AutoShutdown Plus

______________________________________________________________________________________

11

0

0

V+

V-

0

INVALID

OUTPUT

OUTPUT

TRANSMITTER

INPUTS

RECEIVER

INPUTS

}

INVALID

REGION

*MAX3224–MAX3227

TRANSMITTER

OUTPUTS

Figure 4b. AutoShutdown Plus,

INVALID, and READY Timing Diagram

FORCEON

MASTER SHDN LINE

0.1

μF1MΩ

FORCEOFF

MAX3224

MAX3225

MAX3226

MAX3227

MAX3244

MAX3245

POWER-

MANAGEMENT

UNIT

Figure 5. AutoShutdown Plus Initial Turn-On to Wake Up a

Mouse or Another System