Triac-output optoisolator for AC load switching
The onsemi FOD4216TV is a single-channel optoisolator with a Triac output stage, designed to switch AC loads from a low-voltage logic or microcontroller signal. The 5000 Vrms isolation rating provides reinforced insulation between the control side and the mains-connected load — suitable for applications requiring a safety barrier per IEC 60950 or IEC 62368. The 600 V off-state voltage rating covers 240 VAC and 277 VAC line switching with derating margin, and the 10 kV/µs minimum static dV/dt means the output triac will not falsely trigger on fast mains transients or inductive load switching edges — a common failure point in random-phase optoisolators used in motor or solenoid drives.
Drive requirements and load interface
The LED side requires a forward voltage of 1.28 V typical and a maximum continuous forward current of 30 mA. With no zero-crossing circuit, the triac fires at whatever phase angle the LED is energized — this is the correct part for phase-control (dimmer) or random-turn-on loads. The 60 µs turn-on time is fast enough to trigger within a few degrees of a 50/60 Hz sine wave, but the designer must account for the propagation delay when synchronizing to the AC zero-cross for partial-cycle firing. The hold current is 500 µA — below this the triac commutates off. In a low-current load (e.g., a small relay coil or indicator lamp), verify the load current stays above Ih across the full operating temperature range to avoid the output dropping out mid-cycle.
Package, approvals, and temperature range
The FOD4216TV comes in a 6-DIP through-hole package with 0.400-inch (10.16 mm) lead spacing. The Bulk packaging means parts are shipped in tubes or trays — no tape-and-reel, so this is a manual-insertion or low-volume automated assembly part. Safety approvals include cUL, FIMKO, UL, and VDE — the part carries recognition for both North American (UL/cUL) and European (VDE, FIMKO) markets, covering the major regulatory jurisdictions for industrial and appliance equipment. ROHS3 compliant with no exempted substances. Operating temperature spans -55°C to 100°C — the full industrial range with extra cold-side margin. The 100°C upper limit means the part can sit in a sealed enclosure near a warm power supply or motor drive without forced cooling, as long as the ambient stays below that ceiling.