ADM485

FEATURES Meets EIA RS-485 standard 5 Mbps data rate Single 5 V supply –7 V to +12 V bus common-mode range High speed, low power BiCMOS Thermal shutdown protection Short-circuit protection Driver propagation delay: 10 ns typical Receiver propagation delay: 15 ns typical High-Z outputs with power off Superior upgrade for LTC485 APPLICATIONS Low power RS-485 systems DTE/DCE interface Packet switching Local area networks (LNAs) Data concentration Data multiplexers Integrated services digital network (ISDN) GENERAL DESCRIPTION The ADM485 is a differential line transceiver suitable for high speed bidirectional data communication on multipoint bus transmission lines. It is designed for balanced data transmission and complies with EIA standards RS-485 and RS-422. The part contains a differential line driver and a differential line receiver. Both the driver and the receiver can be enabled independently. When disabled, the outputs are three-stated. The ADM485 operates from a single 5 V power supply. Excessive power dissipation caused by bus contention or by output shorting is prevented by a thermal shutdown circuit. If during fault conditions, a significant temperature increase is detected in the internal driver circuitry, this feature forces the driver output into a high impedance state. Up to 32 transceivers can be connected simultaneously on a bus, but only one driver should be enabled at any time. It is important, therefore, that the remaining disabled drivers do not load the bus. ...