Isolation and signal transfer
The onsemi CNY17F1M is a single-channel optocoupler with a phototransistor output, rated for 4170 Vrms isolation between input and output — enough to separate a 24 VDC PLC input from a 230 VAC motor drive bus in an industrial panel. Current transfer ratio spans 40% to 80% at a forward current of 10 mA, so the output transistor saturates with a 4 mA to 8 mA collector current from a 10 mA LED drive — the 400 mV Vce(sat) ceiling keeps the logic-level drop low enough for a 5 V TTL input.
Switching speed and output ratings
Turn-on time is 2 µs typical, turn-off 3 µs typical, with a 4 µs rise and 3.5 µs fall — fast enough to pass a 100 kHz digital signal without pulse-width distortion, but the 50 mA maximum output current limits the load to a single logic gate input or a low-power relay coil. The output transistor blocks up to 70 V, so it interfaces directly with 24 V and 48 V industrial buses without an external clamp.
Housed in a 6-DIP (0.300-inch, 7.62 mm pitch) through-hole package, the CNY17F1M mounts into a standard 0.100-inch grid PCB — the 0.300-inch row spacing matches legacy DIP sockets and wave-solder processes. Supplied in tubes, the part is pick-and-place compatible with tube feeders for medium-volume assembly.