The CNY172S is listed as obsolete by onsemi, meaning the manufacturer has discontinued production. No pin-compatible direct replacement is documented from onsemi.
Isolation and signal transfer — what the ratings mean
Rated for 5300Vrms isolation, this optocoupler provides galvanic separation between the DC input side and the transistor output — suitable for safety barriers in industrial controls, PLCs, and power-supply feedback loops where transient isolation is required. The current transfer ratio (CTR) spans 63% to 125% at a forward current of 10 mA, which defines the minimum output current the phototransistor can sink for a given LED drive — a 63% floor ensures the downstream logic sees a valid high even with LED degradation over temperature and time. With a typical turn-on time of 2 µs and turn-off of 3 µs, the CNY172S switches at speeds adequate for 100 kHz-class signals — the 1 µs rise and 2 µs fall times are consistent with a standard phototransistor output, not a high-speed logic gate.
Housed in a 6-SMD Gull Wing package (supplier device package 6-SMD), the part is a surface-mount optocoupler with a standard 7.62 mm pitch — the gull-wing leads are compatible with reflow soldering and visual inspection. Operating temperature range of -55°C to 100°C covers industrial and some automotive under-hood environments — the upper limit is 100°C, so derating is needed if the ambient near the optocoupler exceeds that.
Sourcing posture
No franchised stock or manufacturer lead time applies.