It integrates one driver and one receiver, with 130 mV of receiver hysteresis for noise rejection on long cable runs.
130 mV hysteresis — noise margin on the bus
The 130 mV receiver hysteresis is the spec that matters for signal integrity on a noisy RS485 bus. It sets the dead band between the logic thresholds, meaning the receiver won't chatter on a slowly rising differential signal or when ground potentials shift between nodes. For a 25 Mbps link over twisted-pair cable in a motor-drive cabinet, that hysteresis budget is what keeps the UART from seeing false edges.
The SN65HVD20D carries a Last Buy lifecycle status. This means TI has issued an end-of-life notice and the part is on its final production run. Once the last-time-buy window closes, the only channel will be surplus and independent distribution.