Triac output with 10 kV/µs dV/dt for noisy mains
The FOD4218SDV is a single-channel triac-output optoisolator from onsemi, designed to switch AC loads while maintaining 5000 Vrms galvanic isolation between control and load sides. Its 10 kV/µs minimum static dV/dt rating means the output triac resists false turn-on from fast voltage transients on the AC line — a common failure in motor-drive and relay-replacement circuits where inductive switching generates high dv/dt edges.
800 V off-state and 1.3 mA LED trigger current
The 800 V off-state voltage allows direct switching of 277 VAC or 480 VAC lines with margin. The maximum LED trigger current of 1.3 mA means a standard 3.3 V or 5 V MCU GPIO can drive it through a series resistor without a separate transistor buffer — saving board space and BOM cost. Typical forward voltage is 1.28 V, and the hold current is 500 µA, which keeps the triac latched once triggered until the load current drops below that threshold near the AC zero crossing.
Active production with multiple agency approvals
ROHS3 compliant. For a tube-packed alternative, the FOD4218SV shares identical electrical ratings — same 10 kV/µs dV/dt, 800 V off-state, and 60 µs turn-on time — differing only in shipping format.