Analog Devices ADM3491E Product Info

The ADM3483E / ADM3486E / ADM3488E / ADM3490E / ADM3491E are 3.3 V low power data transceivers with ±15 kV ESD protection suitable for full and half-duplex communication on multipoint bus transmission lines. They are designed for balanced data transmission and comply with TIA/EIA standards RS-485 and RS-422. The ADM3483E / ADM3486E is a half-duplex transceiver that shares differential lines and has separate enable inputs for the driver and receiver. The full-duplex ADM3488E / ADM3490E / ADM3491E transceivers have dedicated differential line driver outputs and receiver inputs. The ADM3491E also features enable inputs for the driver and receiver.

The devices have a 12 kΩ receiver input impedance which allows up to 32 transceivers on a bus. Since only one driver should be enabled at any time, the output of a disabled or powered down driver is three-stated to avoid overloading the bus. The driver outputs of the ADM3483E / ADM3486E / ADM3488E are slew rate limited in order to reduce EMI and data errors caused by reflections from improperly terminated buses. The receiver has a failsafe feature which 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 parts are fully specified over the industrial temperature ranges and are available in narrow 8-lead and 14-lead (ADM3491E) SOIC packages.