Rugged RS485 transceiver offers greater robustness and signal integrity

Linear Technology has announced the LTC2862A, an enhanced version of the LTC2862 ±60V tolerant RS485/RS422 transceiver that released several years ago. Both of these half-duplex transceivers eliminate field failures without the need of costly external protection devices by protecting practical RS485 systems from installation cross-wiring faults, ground voltage faults or lightning induced surge voltages, which can cause overvoltage conditions that exceed the absolute maximum ratings of typical transceivers. Both devices operate from supply voltages of 3V to 5.5V while maintaining compliance with the TIA/EIA-485-A standard. However, the device boosts its predecessor’s ESD protection and noise immunity with higher specifications including unprecedented ±40kV HBM and IEC Level 4 ESD ratings, resulting in greater robustness and signal integrity. The device provides valuable protection and reliability for a wide range of RS485/RS422 applications, including industrial control, instrumentation networks and automotive electronics. Whether a circuit is transmitting, receiving, in standby or powered off, the device tolerates any voltage within ±60V without damage. An extended ±25V input common mode range increases the reliability of operation and extends functionality to environments with high common mode voltages. Fully symmetric receiver thresholds ensure good duty cycle symmetry at low signal levels, and additional filtering prevents errors from high frequency noise, providing optimal full failsafe operation. Markedly improved ESD protection allows the device to withstand ±40kV HBM (IEC-61000-4-2 ESD Level 4: ±8kV) on the transceiver pins without latchup or damage; all other pins are protected to ±15kV HBM. It also guards against EFTs with IEC 610004-4 EFT Level 4: ±5kV protection.