5300Vrms isolation in a 6-DIP through-hole package
The onsemi CNY17F4300 is a single-channel phototransistor optocoupler in the standard 6-DIP (0.300", 7.62mm) through-hole package. It provides 5300Vrms galvanic isolation between a DC input LED and a phototransistor output — sufficient for reinforced insulation in mains-connected industrial control interfaces, SMPS feedback loops, and PLC digital input modules where the safety barrier must withstand 250VAC working voltage with margin. The 160% to 320% current transfer ratio at 10mA forward current means the phototransistor saturates reliably with modest LED drive, keeping the input-side power budget low in 24V PLC or 5V logic circuits. The 70V output breakdown and 50mA continuous output current handle typical logic-level loads and low-power relay coils without an external buffer.
Switching speed and temperature range for the BOM
With 1µs typical rise and 2µs typical fall times, and 2µs turn-on / 3µs turn-off, the CNY17F4300 switches comfortably at data rates up to about 100 kbps — adequate for 50/60Hz zero-cross detection, status feedback, and low-speed serial isolation. The -55°C to 100°C operating temperature range covers industrial enclosures and outdoor telecom cabinets without derating. The 300mV maximum Vce saturation at rated current ensures the output drops less than a logic-low threshold when driving a TTL or CMOS input — no pull-up resistor adjustment needed when replacing an older optocoupler in the same footprint.
onsemi has marked the CNY17F4300 as Obsolete. No direct successor order code is listed by the manufacturer. For a BOM line that requires the 6-DIP footprint and 5300Vrms isolation, the CNY17F4300 is a drop-in fit. Confirm the CTR bin (160-320% at 10mA) matches the original design's minimum transfer ratio before committing.