70-V Fault-Protected RS-485 Transceiver With Cable Invert

These devices are designed to survive overvoltage faults such as direct shorts to power supplies, mis-wiring faults, connector failures, cable crushes, and tool mis-applications. They are also robust to ESD events, with high levels of protection to human-body model specifications.

These devices combine a differential driver and a differential receiver, which operate from a single power supply. The driver differential outputs and the receiver differential inputs are connected internally to for a bus port suitable for half-duplex (two-wire bus) communication. A cable invert pin (INV) allows active correction of mis-wires that may occur during installation. Upon detecting communication errors, the user can apply a logic HIGH to the INV pin, effectively inverting the polarity of the differential bus port, thereby correcting for the reversed bus wires.

These devices feature a wide common-mode voltage range, making them suitable for multi-point applications over long cable runs. These devices are characterized from –40°C to 105°C.

For similar features with 3.3 V supply operation, see the SN65HVD1781 (SLLS877).