The ADM488A andADM489Aare low power, differential line transceivers suitable for communication on multipoint bus transmission lines. They are intended for balanced data transmission and comply with both RS-485 and RS-422 standards of the Electronics Industries Association (EIA). Both products contain a single differential line driver and a single differential line receiver, making them suitable for full-duplex data transfer. The ADM489A contains an additional receiver and driver enable control.The input impedance is 12 kΩ, allowing 32 transceivers to be connected on the bus. The ADM488A / ADM489A operate from a single 5 V ± 10% power supply.Excessive power dissipation that is caused by bus contention or output shorting is prevented by a thermal shutdown circuit. This feature forces the driver output into a high impedance state if, during fault conditions, a significant temperature increase is detected in the internal driver circuitry. The receiver contains a fail-safe feature that results in a logic high output state if the inputs are unconnected (floating).The ADM488A / ADM489A are fabricated on BiCMOS, an advanced mixed technology process combining low power CMOS with fast switching bipolar technology.The ADM488A / ADM489A are fully specified over the industrial temperature range and are available in SOIC and MSOP packages.APPLICATIONSLow power RS-485 and RS-422 systemsDTE-DCE interfacePacket switchingLocal area networksData concentrationData multiplexersIntegrated services digital network (ISDN)