美信正MAX3471EUA/MAX3471EUA+

the max3471 half-duplex transceiver is intended for lithium battery-powered rs-485/rs-422 applications. it draws only 1.6µa (typical) supply current from a 3.6v supply with the receiver enabled and the driver disabled. its wide 2.5v to 5.5v supply voltage guarantees operation over the lifetime of a lithium battery.

this device features true fail-safe operation that guarantees a logic-high receiver output when the receiver inputs are open or shorted. this means that the receiver output will be a logic high if all transmitters on a terminated bus are disabled (high impedance). the max3471 has a 1/8-unit load input resistance. when driver outputs are enabled and pulled above vcc or below gnd, internal circuitry prevents battery back-charging.