5000Vrms isolation in a field-swappable DIP
It comes in a 6-DIP through-hole package (0.300" body width), which means you can swap it on site with a standard desoldering tool — no hot-air station needed. On the output side, the phototransistor (with base terminal brought out) can switch up to 70V and sink 50 mA continuous.
CTR range — what 160% to 320% means for your BOM
The current transfer ratio is specified at 10 mA forward current: minimum 160%, maximum 320%. That spread matters when you are designing a logic-level interface or a PLC input module — the 160% floor guarantees the output transistor will saturate (Vce sat max 300mV) with a known collector load, while the 320% ceiling tells you the worst-case drive current into the base. If you are replacing a 4N35-class part in an existing design, check whether the original CTR bin matches; the CNY75C's 160-320% range is tighter than the 4N35's 100-600%, which can reduce the resistor-trimming headache on the production line.
Switching is on the slower side — turn-on typ 7 µs, turn-off 5 µs, rise/fall 4.2/4.7 µs — fine for 50/60 Hz mains sensing, relay drivers, and DC bus voltage feedback. Not the part for high-speed digital isolation above a few kHz.