RS-485 transceiver offers fastest automatic polarity correction

September 06, 2013 // By Graham Prophet
TI has introduced a low-power transceiver that increases reliability in e-metering and industrial applications

Texas Instruments' low-power, half-duplex RS-485 transceiver claims the fastest automatic bus-polarity correction time. In many industrial applications, such as e-metering networks, DMX512 networks, industrial automation, HVAC systems and process control, it is easy to connect wires incorrectly, which can cause system failure. For large networks, mis-wiring without quick correction can cause production delays, resulting in significant revenue loss. When hot-plugged, the SN65HVD888 provides cross-wire immunity 80% faster than other parts, detecting and correcting the bus polarity within 76 msec of bus idling.

SN65HVD888 is available in a standard 8-pin SOIC package, which eliminates the need for board redesign while providing a robust, reliable upgrade to a standard RS-485 device. In addition, the SN65HVD888 supports up to 256 nodes on the bus, eliminating the need for repeaters.

It offers better electrostatic discharge (ESD)/electrical fast transients (EFT) performance: At ±12 kV IEC61000-4-2 contact discharge and +4 kV IEC61000-4-4 fast transient burst, it is more reliable in noisy environments. Highest transient immunity comes with large receiver hysteresis at 60 mV, 15% higher than the nearest competitor, providing better immunity to noise on the bus lines. An optimised combination of low quiescent and standby supply currents makes the device suitable for battery-powered applications.

The RS-485 half-duplex evaluation module, $49, is available to evaluate device performance, to support fast development and analysis of data transmission systems using the SN65HVD888. The part costs $1.10 (1,000).