The Vishay VO2223B is a single-channel phototriac output optocoupler in a through-hole 8-DIP package with 7 leads. It switches AC loads up to 1 A RMS at 600 V off-state voltage, with 4470 Vrms isolation between the LED input and the triac output. The part is typically used for resistive-load switching in industrial controls, solid-state relays, appliance power switching, and AC motor starters where galvanic isolation is required between a low-voltage logic circuit and the mains line.
1 A RMS and 600 V off-state — the load-handling reality
The 1 A RMS on-state current is a continuous rating for resistive loads like heaters, incandescent lamps, and solenoid valves. For inductive loads — motors, contactors, transformers — the triac's turn-off dV/dt immunity of 600 V/µs (typical) is high enough that many designs can omit the external snubber, saving board space and BOM cost. The 600 V off-state voltage covers 240 VAC mains with margin for line surges up to 400 V peak.
No zero-crossing — phase-control freedom
The VO2223B has no internal zero-crossing circuit, so the triac can be triggered at any point in the AC cycle. This enables phase-angle dimming for incandescent lamps or soft-start for motors, but for inductive loads the lack of zero-crossing means the designer should evaluate snubber requirements at the maximum dV/dt the load generates. The 600 V/µs typical static dV/dt gives a wide margin for most industrial loads.
LED drive — logic-compatible trigger
The LED forward voltage is 1.4 V max, and the LED trigger current (Ift) is 10 mA max. The maximum DC forward current is 50 mA, so the resistor value should be chosen to keep the LED current between 10 mA and 50 mA. A 330 Ω resistor from a 5 V output gives about 12 mA, well within the trigger threshold.
Isolation and approvals
The 4470 Vrms isolation rating qualifies the VO2223B for reinforced insulation between low-voltage control circuits and mains AC. It carries cUR and UR approval, which simplifies certification for North American safety standards.
Lifecycle and sourcing posture
It is ROHS3 compliant. No end-of-life risk for new designs.