资 源 简 介
The ADM1490E/ADM1491E are RS-485/RS-422 transceivers with ±8 kV ESD protecTIon and are suitable for high speed， fullduplex communicaTIon on mulTIpoint transmission lines. In parTIcular， the ADM1490E/ADM1491E are designed for use in motor control applications requiring communications at data rates up to 16 Mbps. The ADM1490E/ADM1491E are designed for balanced transmission lines and comply with TIA/EIA-485-A-98. The devices each have a 12 kΩ 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 ADM1490E/ADM1491E operate 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 ADM1490E/ADM1491E contains a fail-safe feature that results in a logic high output state if the inputs are unconnected （floating）。 The ADM1490E/ADM1491E feature extremely fast and closely matched switching times. Minimal driver propagation delays permit transmission at data rates up to 16 Mbps， and low skew minimizes EMI interference. The ADM1490E/ADM1491E are fully specified over the commercial and industrial temperature ranges. The ADM1490E is available in two packages： a narrow body， 8-lead SOIC and an 8-lead MSOP. The ADM1491E is also available in two packages： a narrow body， 14-lead SOIC and a 10-lead MSOP.
