Isolation barrier and signal transfer
The 4N37SR2M from onsemi is a single-channel optoisolator with a 4170Vrms isolation rating — enough to separate control logic from a 240VAC motor drive or a medical patient-contact circuit. The DC input drives an infrared LED; the output is a phototransistor with the base brought out, giving you the option to bias the transistor for faster switching or to tie the base to emitter for a standard phototransistor configuration. Minimum current transfer ratio of 100% at 10mA forward current means the output can sink at least as much current as the LED draws — a 10mA input yields 10mA output, which directly drives TTL or CMOS logic without a buffer stage. Typical turn-on and turn-off times are 2µs each, fast enough for 100kHz switching or PLC input sampling.
Package and temperature range for industrial boards
Housed in a 6-SMD gull-wing package (supplier device package 6-SMD), the 4N37SR2M is a surface-mount part suited for reflow assembly. The 30V maximum output voltage and 300mV Vce saturation at rated current mean the output side can interface with 3.3V or 5V logic rails directly; the low saturation voltage keeps power dissipation minimal in the output transistor.
ROHS3 compliant, so it fits EU and global environmental requirements without exemption paperwork. Sourced to order against your BOM line — confirm quantity and preferred packaging when requesting a quote.