Isolation barrier and signal transfer
The onsemi CNY173M is a single-channel optoisolator with a 4170Vrms isolation rating, DC input, and a phototransistor output with base connection. The 6-DIP through-hole package (0.300-inch body width) suits boards where creepage distance matters — the 7.62 mm pin pitch plus the moulded body provide a physical isolation barrier that holds the 4170Vrms test voltage without surface tracking over time.
Switching speed and drive margin
Turn-on and turn-off times are 2 µs and 3 µs typical, with rise and fall edges at 4 µs and 3.5 µs max — fast enough for 100 kHz-level signalling in PLC digital inputs or isolated feedback loops in motor drives, but not for high-speed serial buses. The base terminal allows the designer to add a pull-down resistor to speed up turn-off or to bias the transistor for linear operation in analog isolation. Output can sink up to 50 mA at 70 V max, with a saturation voltage of 400 mV at the rated current — this drives a standard 5 V or 24 V logic input directly through a collector resistor without an extra buffer stage.
Temperature range and compliance
The forward voltage is 1.35 V typical at 10 mA, and the absolute maximum forward current is 60 mA — stay below this to avoid degrading the LED over life. Lifecycle status is Active and the part is ROHS3 compliant. Sourced through independent distribution; availability and current pricing confirmed at RFQ.