5300 Vrms isolation, 800 V off-state — Triac-output optocoupler for industrial AC switching
The Vishay VO4258H-X007T is a single-channel optoisolator with a Triac output, designed to drive AC loads from a logic-level control side with galvanic isolation. Its 5300 Vrms isolation rating qualifies it for reinforced insulation in mains-connected equipment — motor drives, solid-state relays, industrial contactors, and HVAC controllers. The output side handles 800 V off-state and conducts up to 300 mA RMS, so it directly switches 240 VAC or 480 VAC loads without an external Triac for moderate current draws. The 5 kV/µs minimum static dV/dt immunity keeps the output from false-triggering on inductive kickback or line transients, a common headache in noisy factory-floor environments.
No zero-crossing — phase-control and random-fire applications
This part has no zero-crossing detection circuit, so the Triac fires at any point in the AC cycle. That makes it the right choice for phase-angle dimming, soft-start motor control, or any application where you need to switch on at a specific phase rather than only at the voltage zero-cross. Forward voltage is typical 1.2 V, and the LED can take up to 60 mA continuous DC — plenty of headroom for derating in high-temperature enclosures.
Surface-mount 6-SMD Gull Wing, -55°C to 100°C
The 6-SMD footprint is shared with other Vishay random-phase Triac-output optocouplers, so a board layout can accommodate multiple current or voltage variants with minor BOM changes.
Active lifecycle, ROHS3 compliant, multiple safety approvals
It is ROHS3 compliant and carries safety approvals from BSI, cUR, FIMKO, and UR, which streamlines acceptance into equipment destined for European and North American markets.