Triac-output optoisolator for AC load switching
The MOC3163SR2M is a single-channel optoisolator from onsemi that integrates a GaAs infrared LED optically coupled to a triac output with a zero-crossing detection circuit. It is designed to drive a power triac or directly switch low-power AC loads up to 600 V off-state while providing 4170 Vrms galvanic isolation between the control and load sides. The zero-crossing feature ensures the output triac turns on only when the AC line voltage is near zero, which limits inrush current and reduces conducted EMI — a practical advantage when switching resistive heaters, solenoid valves, or incandescent lamps.
Parametric fit for AC line control
The 600 V off-state voltage covers 120/240 VAC mains with a 2.5× voltage margin, suitable for industrial motor starters and HVAC contactor coils. The minimum static dV/dt of 1 kV/µs provides immunity to fast voltage transients from inductive load switching — a common failure mode in relay-driver circuits where false triggering can cause partial conduction and overheating. The LED trigger current maximum of 5 mA allows direct drive from 3.3 V or 5 V logic outputs through a series resistor, simplifying the interface. Typical holding current is 500 µA, which means the triac output will commutate off cleanly when the load current drops below this threshold near the AC zero crossing.
Lifecycle and sourcing status
It is ROHS3 compliant and carries UL approval. The part is supplied in Tape & Reel (TR) or Cut Tape (CT) in the 6-SMD Gull Wing package.
Package and mounting considerations
The 6-SMD Gull Wing package has a 2.54 mm (0.100 inch) pin pitch compatible with standard SOIC-6 footprints. The gull-wing leads provide visual solder-joint inspection access. The operating temperature range of -40°C to 85°C covers industrial control cabinets and outdoor telecom enclosures without derating. No exposed thermal pad — the package relies on ambient air cooling; for high-density boards, ensure adequate clearance around the part for convection.