Analog Devices ADM3485E Low Power Data Transceiver provides ±15kV ESD protection and is suitable for half-duplex communication on multipoint bus transmission lines. The ADM3485E is designed for balanced data transmission and complies with TIA/EIA standards RS-485 and RS-422. The ADM3485E is a half-duplex transceiver that shares differential lines and has separate enable inputs for the driver and the receiver. The devices have a 12kΩ receiver input impedance, which allows up to 32 transceivers on a bus. Because only one driver should be enabled at any time, the output of a disabled or powered-down driver is tristated to avoid overloading the bus. The receiver has a fail-safe feature that ensures a logic high output when the inputs are floating. Excessive power dissipation caused by bus contention or by output shorting is prevented with a thermal shutdown circuit.