ADM1491E

The ADM1491E is an RS-485 transceiver with ±8 kV ESD protection and is suitable for high speed, full-duplex communication on multipoint transmission lines. In particular, the product is designed for use in motor control applications requiring communications at data rates up to 16 Mbps. The ADM1491E is designed for balanced transmission lines and complies with TIA/EIA-485-A-98.

The device has a 12 k receiver input impedance for unit load RS-485 operation allowing up to 32 nodes on the bus. The differential transmitter outputs and receiver inputs feature electrostatic discharge circuitry that provides protection to ±8 kV using the human body model (HBM). The ADM1491E operates from a single 5 V power supply. Excessive power dissipation caused by bus contention or output shorting is prevented by short-circuit protection and thermal circuitry. Short-circuit protection circuits limit the maximum output current to ±250 mA during fault conditions.

A thermal shutdown circuit senses if the die temperature rises above 150°C and forces the driver outputs into a high impedance state under this condition. The receiver of the ADM1491E contains a fail-safe feature that results in a logic high output state if the inputs are unconnected (floating). The product features extremely fast and closely matched switching times. Minimal driver propagation delays permit transmission at data rates up to 16 Mbps while low skew minimizes EMI interference.

The ADM1491E is fully specified over the commercial and industrial temperature ranges and is available in two packages: a narrow-body 14-lead SOIC and a 10-lead MSOP.