Darlington optoisolator with base access
The H11G1M is a single-channel optoisolator from onsemi with a Darlington output that includes a base terminal — a feature that lets you tailor the switching threshold or add a speed-up capacitor. The 1000% minimum current transfer ratio at 10 mA forward current means a 10 mA LED drive can saturate the output transistor, pulling the collector low with only a 1 V drop across it. That high gain is the reason this part is chosen for driving relays, solenoids, or PLC input modules where the microcontroller I/O can't source much current. Input side is DC-only. The forward voltage is 1.3 V typical, and the LED can handle up to 60 mA continuous. On the output side, the collector-emitter rating is 100 V maximum.
Isolation and temperature envelope
Isolation is rated at 4170 Vrms — enough for reinforced insulation in mains-referenced circuits like motor drives, power supplies, and industrial sensors. Packaged in a 6-DIP through-hole body with 0.300-inch (7.62 mm) pin spacing — a standard footprint that mates with sockets or wave-solder processes.
onsemi lists the H11G1M as Active and ROHS3 compliant.