The onsemi H11A33S is a single-channel optocoupler with a DC-input LED and a phototransistor output that brings out the base terminal — useful when you need to bias the output transistor for faster switching or lower saturation voltage in a specific collector-current range. Rated for 5300Vrms isolation, this part handles the galvanic barrier in industrial controls, motor-drive feedback, and PLC digital input modules where the field side must stay isolated from the controller ground. Minimum current transfer ratio is 20% at 10mA forward current, and the typical turn-on and turn-off times are both 2µs — fast enough for 24V DC discrete signals at switching frequencies up to a few hundred hertz without pulse-stretching concerns. Operating temperature spans -55°C to 100°C, covering industrial and some automotive under-hood environments where the ambient stays below the 100°C ceiling.
Housed in a 6-SMD gull wing package (6-SMD per JEDEC), the H11A33S mounts on the PCB surface with a standard 1.27mm pin pitch — the same footprint as the DIP-6 through-hole version but reflow-compatible. Supplied in tubes, not tape-and-reel — factor this into the pick-and-place feeder setup if running high-volume assembly; a tube-fed or tray-fed handler is needed.