Triac Driver for Isolated AC Load Switching
The MOC3023TVM is a 1-channel optoisolator with a triac output rated for 400 V off-state voltage, making it suitable for switching 120 VAC or 240 VAC loads through an external power triac or SCR. The non-zero-crossing output allows random-phase turn-on, which is essential for phase-control applications such as incandescent dimmers, universal motor speed controls, and heater proportional controllers where the trigger angle must be adjustable across the AC cycle. The typical forward voltage of 1.15 V at the LED is compatible with 3.3 V and 5 V logic rails.
Isolation and Safety Ratings for Mains Interfaces
The 4170 Vrms isolation voltage provides reinforced insulation between the low-voltage control side and the high-voltage AC line, meeting the requirements of IEC/EN/DIN and UL safety standards. This rating is critical for passing regulatory safety tests in appliance, lighting, and industrial control designs where the optoisolator bridges the gap between a microcontroller and a live AC circuit. The 6-DIP package with 0.400-inch (10.16 mm) lead spacing supports the creepage and clearance distances needed for 250 Vrms working voltage in pollution degree 2 environments. The through-hole mounting is preferred in designs where vibration resistance and manual rework access are priorities over board density.
Active Lifecycle and Sourcing Reality
The base product number MOC302 spans a family of zero-crossing and non-zero-crossing variants in the same 6-DIP footprint, so if a future BOM change requires a zero-crossing version, the MOC3020 or MOC3021 series are pin-compatible alternatives within the same package. RoHS3 compliant — no exemption-based lead content.
Holding Current and Trigger Sensitivity
The typical holding current (Ih) is 100 µA, which means the internal triac will latch on once triggered and remain conducting until the load current drops below this threshold near the AC zero crossing. This is a standard value for driving a sensitive-gate power triac; the external triac's gate resistor should be sized to ensure the opto's output current exceeds Ih during the trigger pulse. The 60 mA maximum DC forward current on the LED side should be derated above 25°C per the onsemi datasheet thermal derating curve.