5300 Vrms isolated triac driver for AC loads
The Vishay VO4256H-X007T is a single-channel optoisolator with a triac output, designed to drive resistive or inductive AC loads from a low-voltage control side while providing 5300 Vrms galvanic isolation. It blocks up to 600 V off-state and conducts up to 300 mA RMS on-state, making it a fit for solenoid valves, small motors, solid-state relays, and triac-driven heater elements in industrial and appliance controls. The 6-SMD Gull Wing package suits surface-mount assembly on mixed-signal boards where isolation between the microcontroller domain and the AC power rail is mandatory.
5 kV/µs dV/dt — false-trigger margin on inductive loads
A minimum static dV/dt of 5 kV/µs means the output triac will not commutate falsely when the AC line sees fast voltage edges from relay bounce, contactor dropout, or nearby switching converters. For a design driving a 24 VAC or 277 VAC inductive load, this rating gives headroom against the dv/dt that back-EMF or line transients produce. The part has no zero-cross circuit, so the triac fires as soon as the LED current exceeds the 2 mA trigger threshold — useful for phase-angle control or when you need turn-on at any point in the AC cycle, not just the zero crossing.
Temperature range and agency approvals
The approvals list — cUR, FIMKO, UR — means the part carries North American and European safety certifications, which shortens the bill-of-materials qualification cycle for equipment sold into those markets. ROHS3 compliance is confirmed, so no exemption paperwork needed for EU or California markets.