5300 Vrms isolation — the spec that decides the fit
The Vishay ILQ615-3X009T is a quad-channel optocoupler in a 16-SMD gull-wing package. Its primary job is galvanic isolation — 5300 Vrms across the isolation barrier — which makes it a candidate for motor drives, industrial PLCs, medical equipment, and any design where you need to pass a DC-level signal across a high-voltage boundary without a ground loop. Each channel uses a DC-input LED driving a phototransistor output. The output transistor can handle up to 70 V and 50 mA per channel, so it can directly drive logic inputs, relay coils through a resistor, or small signal loads without an extra buffer.
Current transfer ratio — 100% to 200% at 10 mA
The CTR is specified as 100% minimum, 200% maximum, both at a forward current of 10 mA. That means with 10 mA through the input LED, the output transistor will sink between 10 mA and 20 mA collector current. The 2:1 spread is typical for phototransistor optos; the designer sizes the collector load resistor for the minimum CTR to guarantee saturation over temperature and lifetime. Switching speed is modest — 2 µs rise and fall typical, 3 µs turn-on and 2.3 µs turn-off typical. This part is not for high-speed data; it is for status signals, fault detection, relay drives, and slow digital isolation where the propagation delay does not matter.
Temperature range and environment
The 16-SMD gull-wing package is rework-friendly — you can swap it with a standard soldering iron, no hot-air station needed, which matters when the board is in a cabinet on site.
Lifecycle and compliance
Product status is listed as active. ROHS3 compliant.