The SN65HVD77D is a full-duplex RS-485/RS-422 transceiver from Texas Instruments rated for 50 Mbps signaling. At that data rate the bus is limited to short cable runs — a few meters — but the throughput suits high-speed backplane links, motor-drive encoder interfaces, and industrial vision systems where the cable stays inside the cabinet. The full-duplex pair means simultaneous transmit and receive on separate twisted pairs, so no direction-toggle latency in the firmware loop. The receiver hysteresis is 70 mV, giving noise immunity on a loaded bus.
TI lists the SN65HVD77D as Active.
3.3 V supply — 5 V logic needs a translator
If the host UART or controller uses 5 V logic levels, the transceiver's input thresholds are not 5 V-tolerant — you need a level shifter or a resistive divider on the DI and RE/DE pins. The RO output swings to VCC, so a 5 V-logic receiver will see a 3.3 V high; that may or may not cross the VIH threshold depending on the controller family. Check the logic-family input thresholds before committing the BOM.
Supplied in an 8-pin SOIC package (body 3.90 mm wide), surface-mount. The footprint is the standard SOIC-8 land pattern — no exposed pad, no thermal-via requirement.