What the dual driver means for your bus
The SN75ALS191DR is a dual-channel RS422/RS485 line driver in an 8-SOIC package — two independent drivers in one 8-pin body, no receivers on die. That 2/0 count means it handles the transmit side of a differential bus only; you pair it with a separate receiver or transceiver for bidirectional links.
Supply rails and temperature grade
Runs on a single 5 V rail, 4.75 V to 5.25 V — the 5 V ±5 % tolerance covers most legacy backplane and industrial supply rails without an extra regulator. The 0 °C to 70 °C commercial temperature grade limits it to indoor, conditioned environments; not rated for the -40 °C industrial or automotive extremes.
Package and footprint reality
8-SOIC with 0.154-inch body width (3.90 mm) and 1.27 mm pin pitch — a standard SOIC-8 footprint that routes easily on two-layer boards. The supplier device package is also 8-SOIC, so the land pattern is the same regardless of which TI packing variant you receive.