Isolation and CTR — the two numbers that decide fit
The CNY172300W: Rated for 5300Vrms isolation, this optoisolator provides a certified safety barrier between mains-tied circuits and low-voltage control logic — suitable for reinforced insulation in power supplies, motor drives, and industrial I/O modules where IEC 60950 or IEC 62368 clearance requirements apply. Current transfer ratio (CTR) is specified as 63% minimum and 125% maximum at a forward current of 10mA. This range guarantees the output transistor saturates reliably across temperature and device variation — critical when driving a logic input or a small relay coil without over-designing the LED drive current. The transistor output with base allows the designer to adjust switching speed or add a pull-up resistor at the base node — a flexibility not available in Darlington or digital-output optoisolators.
Switching speed and output drive
Typical rise time is 1µs and fall time 2µs; turn-on time is 2µs and turn-off 3µs. This suits low-frequency logic-level signals up to about 100 kHz — fast enough for PLC input modules, relay drivers, and isolated serial communication (e.g., RS-232 at 115.2 kbps), but not for high-speed data links. Output is rated for 50mA continuous at a maximum Vce of 70V. This drives small relays, DC loads, or logic gates directly; for higher loads an external transistor buffer is needed.
Package and temperature grade
Housed in a 6-DIP through-hole package (0.400-inch, 10.16mm body width), with a supplier device package of 6-DIP. The through-hole format is rework-friendly and survives hand-soldering or wave-solder — no moisture sensitivity level (MSL) concern, no bake-out required before assembly. The 100°C upper limit restricts use in hot engine bays or high-ambient enclosures without derating.