Isolation barrier and CTR — the fit decision
The CNY17F4 provides 5300Vrms galvanic isolation between a DC input LED and a phototransistor output — this is the rating that determines whether the barrier holds under transient overvoltage in equipment connected to mains or motor drives. Current transfer ratio is specified as 160% min and 320% max at If=10mA — this band tells you the output current you can expect for a given forward current, which sets the load resistor and logic threshold in the receiving circuit. With a Vce saturation of 300mV max and output voltage rated to 70V, the transistor side can drive a 50mA load directly — suitable for PLC digital inputs, relay coils, or level shifting across the isolation boundary.
The operating temperature range of -55°C to 100°C covers industrial and some military-grade environments, but the obsolete status means new designs should evaluate a current-production optoisolator from the same or a compatible family.
Housed in a 6-DIP (0.300", 7.62mm) through-hole package with a supplier device package of 6-DIP — the standard 0.100-inch pitch DIP footprint that mates with breadboards, sockets, or soldered into a PCB. Delivered in tube packaging. Rise and fall times are 1µs and 2µs typical; turn-on and turn-off times are 2µs and 3µs typical — this switching speed is adequate for 100 kbps data rates or low-frequency signal isolation in industrial control loops.