By Analog Devices Inc 93
ADI's ADM3485E is a 3.3 V, low-power data transceiver with ±15 kV ESD protection, suitable for half-duplex communication on multipoint bus transmission lines. The ADM3485E is designed for balanced data transmission, and complies with TIA/EIA standards RS485 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 12 kΩ 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.
The part is fully specified over the industrial temperature range and is available in an 8-lead narrow SOIC package.