The CNY17F23SD: For BOM continuity, a functional replacement will require a parametric match on isolation voltage (5300Vrms), CTR range (63-125% at 10mA), and package (6-SMD Gull Wing).
Isolation and signal-transfer parametrics
Rated for 5300Vrms isolation — this is the galvanic barrier between the DC input LED and the phototransistor output, certified for reinforced insulation in mains-isolated power supplies and industrial interface circuits. Current transfer ratio (CTR) is specified at 63% min, 125% max, measured at If=10mA — this spread defines the input-drive margin the designer must budget across temperature and LED ageing. Switching is characterised by 1µs rise / 2µs fall time (typ) and 2µs turn-on / 3µs turn-off time (typ) — adequate for 50-60 Hz line synchronisation and low-speed logic isolation, but too slow for high-frequency PWM or serial data links.
Output ratings and temperature range
Output transistor withstands up to 70V Vce and 50mA continuous collector current — suitable for driving 24V PLC inputs, relay coils, or DC loads within the current limit. Vce(sat) is clamped at 300mV max at the rated collector current — the saturation voltage is low enough to keep power dissipation in the phototransistor under 15mW at 50mA, avoiding thermal runaway at high ambient. Full -55°C to 100°C operating temperature range covers industrial and outdoor enclosures — the LED forward voltage (1.35V typ at 10mA) shifts about -2mV/°C, so the input drive circuit must hold the LED current within the 100mA absolute maximum across temperature.