3.3V, Full Duplex, 840A, 20M, EIA RS-485 Transceiver

The ADM3491-1 is a low power, differential line transceiver designed to operate using a single 3.3 V power supply. Low power consumption, coupled with a shutdown mode, makes it ideal for power-sensitive applications. It is suitable for communication on multipoint bus transmission lines.

The ADM3491-1 is intended for balanced data transmission and complies with both Electronic Industries Association (EIA) Standards RS-485 and RS-422. It contains a differential line driver and a differential line receiver, making it suitable for full-duplex data transfer.

The input impedance is 19 kΩ, allowing up to 50 transceivers to be connected on the bus. A thermal shutdown circuit prevents excessive power dissipation caused by bus contention or by output shorting. This feature forces the driver output into a high impedance state if a significant temperature increase is detected in the internal driver circuitry during fault conditions.

If the inputs are unconnected (floating), the receiver contains a fail-safe feature that results in a logic high output state.

The ADM3491-1 is fabricated on BiCMOS, an advanced mixed technology process combining low power CMOS with fast switching bipolar technology.

APPLICATIONS

* Telecommunications

* DTE–DCE interface

* Packet switching

* Local area networks

* Data concentration

* Data multiplexers

* Integrated services digital network (ISDN)

* AppleTalk Industrial controls

* Operates with 3.3 V supply

* EIA RS-422 and RS-485 compliant over full CM range

* 19 kΩ input impedance

* Up to 50 transceivers on bus

* 20 Mbps data rate

* Short-circuit protection