Quad-channel isolation in a 16-pin SMD package
The Vishay ILQ1-X009 is a quad-channel optocoupler packing four independent transistor-output channels into a single 16-SMD gull-wing package. Each channel handles a DC input and provides galvanic isolation rated at 5300Vrms, making it a space-efficient choice for multi-channel isolation in industrial controls, PLC I/O modules, motor-drive feedback paths, and isolated serial interfaces.
The 5300Vrms isolation voltage is the headline number that decides where this part fits. That rating qualifies it for reinforced insulation in mains-connected equipment — think isolated power-supply feedback loops, AC motor-drive gate-drive interfaces, and medical-device signal isolation where patient safety demands a high isolation barrier. The 1.9µs rise and 1.4µs fall times (typical) are fast enough for 10–100 kHz switching signals but not for high-speed data — this is an optocoupler for control and status, not for gigabit comms.
CTR and output drive — sizing the load correctly
The 20% to 300% CTR range at 10mA forward current is the spec you need to guarantee the output transistor saturates at the far end of the cable or across temperature. At the 20% minimum, 10mA in gives you 2mA out — enough to pull a 5V logic input low through a 2.2kΩ pull-up. At the 300% maximum, the same input gives 30mA drive, which can switch a small relay or an LED indicator directly. The 400mV Vce saturation maximum means the output drops less than half a volt when fully on, so the logic threshold stays clean. Watch the 60mA absolute maximum forward current — the LED side is the fragile part; a series resistor sized for 10–20mA typical gives good CTR margin without overstressing the emitter.