5000Vrms isolation for line-voltage switching
The FOD4208V is a single-channel optoisolator from onsemi with a triac output, rated for 5000Vrms isolation and 800V off-state voltage. This combination makes it suitable for switching 240V AC loads in industrial motor drives, HVAC contactors, and solid-state relay applications where galvanic isolation between the low-voltage control side and the high-voltage load side is mandatory. With a static dV/dt of 10kV/µs minimum, the output triac resists false turn-on from fast voltage transients — a common failure mode when switching inductive loads such as motors or solenoids. The non-zero-crossing output enables phase-angle control for dimming or soft-start, unlike zero-crossing optotriacs that only trigger at the AC zero point.
Trigger current and thermal margin
Forward voltage is 1.28V typical at If=30mA, so the control-side power budget stays modest even in multi-channel designs. The 500µA hold current means the triac stays latched once triggered until the load current drops below that threshold — relevant for minimum-load scenarios like small fans or LED lamps that might not draw enough current to keep the triac conducting.
Active production, through-hole package
It is in a 6-DIP through-hole package, which is a standard footprint for optoisolators and easy to hand-assemble or wave-solder. The supplier device package is 6-DIP. Approvals include cUL, FIMKO, UL, and VDE, which streamlines safety certification for end equipment sold into North American and European markets. ROHS3 compliance is confirmed.