5300Vrms isolation in a 16-SMD quad pack
The ILQ620-X009T is a four-channel optocoupler from Vishay that packs 5300Vrms of galvanic isolation into a 16-pin SMD gull-wing package. Each channel takes an AC or DC input on the LED side and gives you a transistor output on the other side — handy when you need to cross a safety barrier with a signal that might swing both ways, like a mains-zero-cross or a relay-coil sense line. Output side runs up to 70V and 50mA per channel, which covers most logic-level interfaces and low-power loads.
Current transfer ratio spans 50% minimum to 600% maximum at 5mA forward current. That wide range means you need to design the pull-up and threshold for the worst-case low end, not the typical. If the downstream logic expects a solid high, size the collector resistor so the 50% CTR still saturates the output transistor. The 400mV Vce saturation max at that same 5mA drive keeps the drop low enough for 3.3V or 5V rails without a level shifter.
Switching speed — 3µs on, 2.3µs off
Turn-on time is 3µs typical, turn-off 2.3µs typical, with rise and fall at 20µs and 2µs respectively. That puts it in the slow-but-reliable camp — fine for 50/60 Hz mains sensing, relay drivers, or status feedback where you don't need high-speed comms. Not the part for a switched-mode feedback loop or a CAN transceiver isolation; those want a faster logic-output coupler.
Temperature range and field-fit
Rated from -55°C to 100°C operating. The low end covers military cold-soak and outdoor enclosures in winter; the 100°C top is typical for industrial cabinet gear but stops short of under-hood automotive or process-control zones that see 125°C. If your panel stays below 100°C ambient, this part is comfortable. The 16-SMD gull-wing footprint is rework-friendly with a standard hot-air station — no hidden pads, no bottom-side thermal slug to worry about.