5300Vrms isolation with 63–125% CTR — the safety barrier and drive margin
The CNY1723S is a 1-channel optoisolator from onsemi with a transistor-with-base output, delivering 5300Vrms galvanic isolation between the DC input and the output side — a rating that meets reinforced insulation requirements for mains-connected equipment in industrial power supplies and motor drives. Its current transfer ratio spans 63% to 125% at a forward current of 10mA, meaning the output transistor saturates reliably across the full CTR window without overdriving the LED — a key parameter for maintaining the on-state voltage below 300mV (Vce(sat) max) over temperature and device lifetime. The output can sink up to 50mA continuous at a maximum collector-emitter voltage of 70V, and the switching speeds — 1µs rise, 2µs fall, 2µs turn-on, 3µs turn-off — support data rates up to roughly 100 kbps in typical logic-level isolation applications.
Industrial temperature range and surface-mount package — deployment context
Rated for -55°C to 100°C operating ambient, the CNY1723S suits outdoor telecom, industrial control cabinets, and under-hood automotive auxiliary circuits where the thermal swing exceeds commercial-grade limits. Housed in a 6-SMD gull-wing package (supplier device package 6-SMD), it mounts on standard surface-mount pads and is compatible with reflow soldering profiles typical for mixed-signal boards — the gull-wing leads provide visual solder-joint inspection access.
onsemi has marked the CNY1723S as obsolete (product status: Obsolete).