Linear Technology has a range of rugged, high voltage tolerant RS485/RS422 transceivers which it says can eliminate field failures without the need of costly external protection devices.
In practical RS485 systems, installation cross-wiring faults, ground voltage faults or lightning induced surge voltages can cause overvoltage conditions that exceed absolute maximum ratings of typical transceivers.
The LTC2862-2865 feature ±60V overvoltage fault protection on the data transmission lines, protecting bus pins during operation and power shutdown. Whether a circuit is transmitting, receiving, in standby or powered off, the LTC2862-2865 tolerate any voltage within ±60V without damage, increasing the robustness of any typical RS485 network.
The low power family supports fast 20Mbit/s and low-EMI slew-rate-limited 250kbit/s data rates, as well as half- and full-duplex versions.
The LTC2862-2865 family provides protection and reliability for a variety of RS485/RS422 applications, including industrial control, instrumentation networks and automotive electronics.
An extended ±25V input common-mode range and full failsafe operation improve data communications reliability in electrically noisy environments and in the presence of ground loop voltages. This extended common-mode range allows the LTC2862-2865 devices to transmit and receive under harsh conditions that would otherwise cause data errors and possible device damage.
Enhanced ESD protection allows these devices to withstand ±15kV (HBM and IEC-1000-4-2 air discharge) on the transceiver pins without latchup or damage; all other pins are protected to ±8kV HBM. Fully symmetric receiver thresholds allow the devices to maintain good duty cycle symmetry at low signal levels and boost receiver noise immunity.
www.linear.com/product/LTC2862