Triac output with 5 kV isolation for AC load switching
The FOD4108TV from onsemi is a single-channel optoisolator with a triac output rated for 800 V off-state voltage and 5000 Vrms isolation — built to switch resistive or inductive AC loads while keeping the control side galvanically isolated. The built-in zero-crossing circuit means the triac turns on only when the AC line voltage is near zero, which limits inrush current and reduces conducted EMI — a practical advantage for driving heaters, solenoids, or small motors from a microcontroller port. With a minimum static dV/dt of 10 kV/µs, the output resists false triggering from fast voltage transients common in motor-drive or relay-coil environments.
Certified isolation and temperature range for industrial control
The FOD4108TV carries CSA, UL, and VDE safety approvals, so the isolation barrier is recognised by the major North American and European agencies — no surprise during a compliance audit. Operating temperature spans -55°C to 100°C, covering most industrial cabinet, HVAC, and appliance applications without requiring a wider-range part.
Package and drive-current requirements for BOM fit
The 6-DIP through-hole package with 0.400-inch (10.16 mm) body width suits boards that already carry DIP footprints — no need to migrate to SMT for this one channel. The LED trigger current (Ift) is 2 mA max, and forward voltage is 1.25 V typ, so a standard 5 V or 3.3 V GPIO with a series resistor can drive it directly without a separate transistor stage. Hold current (Ih) is 500 µA — ensure the load current stays above this level to keep the triac latched once triggered, or add a dummy load for very low-current loads.