Quad-channel isolation in a 16-DIP through-hole package
The Vishay CNY74-4H is a quad-channel phototransistor optocoupler in a 16-DIP (0.300", 7.62mm) through-hole package. It provides 5300Vrms galvanic isolation between input and output, with each channel using a DC-input LED driving a phototransistor output. The four independent channels in one DIP save board space and per-channel placement cost compared to using four single-channel optocouplers. The current transfer ratio (CTR) spans 50% minimum to 600% maximum at a forward current of 5mA, giving designers wide latitude in setting the LED drive current and the load resistor for the output transistor. Typical rise and fall times are 3µs and 4.7µs respectively, with turn-on and turn-off times of 6µs and 5µs — adequate for 50/60Hz line-frequency isolation, relay drivers, and digital input modules where microsecond response is acceptable.
5300Vrms isolation — where it fits in the BOM
The 5300Vrms isolation voltage qualifies this part for reinforced insulation in industrial AC-mains interfaces, motor drive feedback, and medical equipment where patient isolation is required. The output transistor is rated for 70V maximum collector-emitter voltage, so it can switch 5V, 12V, or 24V logic and control rails directly. Vce saturation is 500mV maximum, keeping power dissipation low when the output is on. The 60mA maximum forward current per LED channel gives headroom for driving the LED at 5mA to 20mA typical, with the CTR curve providing predictable gain across that range.