4170Vrms isolation for motor-drive and PLC noise barriers
The 4N25SR2M is a single-channel optoisolator from onsemi that breaks ground loops with 4170Vrms isolation — enough to keep 480VAC drive transients off the logic side. The DC input drives an IR LED; the output is a phototransistor with a base pin, so you can bias the transistor for faster switching or use it as a simple switch. The 20% minimum CTR at 10mA forward current means you need at least 2mA on the output side to pull a logic line low — factor that into your pull-up resistor value.
Switching speed and output drive for 24V logic rails
Turn-on and turn-off times are both 2µs typical, which limits the data rate to about 250 kbps — fine for PLC input modules, relay replacement, or status feedback, but not for high-speed serial links. The output transistor is rated for 30V collector-emitter, so it sits comfortably on 24V PLC rails with headroom for spikes. The base pin is brought out — you can add a resistor to ground to speed up turn-off, or leave it open for standard operation.
Active production, surface-mount assembly, industrial temperature range
The 6-SMD gull-wing package is pick-and-place friendly and reflow-solderable — no hand-soldering required unless you are doing a field repair. Operating from -40°C to 100°C, it covers outdoor cabinets, factory floors, and under-hood environments without derating.