The Renesas PS2815-4-F3-A is a quad-channel phototransistor optocoupler from the NEPOC series, packing four isolated transistor-output channels into a 16-SOIC package. It accepts both AC and DC input drive, with a guaranteed current transfer ratio (CTR) of 100% to 400% at 1 mA forward current — wide enough to tolerate LED aging and temperature drift without redesigning the bias resistor. The 2500Vrms isolation rating suits it for breaking ground loops in industrial I/O modules, PLC digital inputs, and motor-drive feedback paths where you need to pass a logic-level signal across a safety barrier.
The 100% minimum CTR at 1 mA If means the output transistor can sink at least 1 mA collector current with 1 mA LED drive — a 1:1 gain floor. The 300 mV max Vce(sat) at the rated output current keeps the logic-low voltage well below the 0.8 V TTL threshold, even with some margin for temperature rise. Rise and fall times of 4 µs and 5 µs typ limit the data rate to about 100 kHz — fine for status signals, relay drivers, and 50/60 Hz zero-cross detection, but not for high-speed serial links.
The NEPOC series is a mature, still-supported Renesas optocoupler family, so supply is steady through franchised and independent channels alike.
Package and temperature — fits a surface-mount assembly line
The 40 V output maximum and 40 mA per-channel current rating give enough headroom for 24 V industrial logic and small relay coils.