Triac output and the non-zero-crossing decision
The MOC3021TVM drives a triac output with no zero-crossing circuit — the output fires immediately when the LED current exceeds the 15 mA max trigger threshold, regardless of the AC line phase. This makes it suitable for phase-control applications such as resistive heater modulation or incandescent dimming, where the triac must turn on mid-cycle. The 400 V off-state voltage rating covers 240 VAC line peaks with margin. Isolation is rated at 4170 Vrms, tested per IEC/EN/DIN and UL standards. The 1.15 V typical forward voltage and 60 mA max LED drive current are standard for this class of phototriac coupler.
Package and board-fit checklist
Through-hole 6-DIP with 0.400-inch (10.16 mm) body width — the wider DIP footprint gives extra pin-to-pin spacing compared to the 0.300-inch narrow DIP. The supplier device package is 6-DIP; no additional heatsinking is required for the phototriac output at typical load currents. Supplied in tube packaging — suitable for hand-insertion or tube-fed auto-insertion equipment. The 100 µA typical hold current ensures the triac output stays latched once triggered, even with low-load currents.