8200Vrms isolation — what it buys you
The Vishay CNY65 is a single-channel, DC-input optoisolator with a transistor output, rated for 8200Vrms of input-to-output isolation. The through-hole package (0.300" lead spacing) is a standard footprint that mates with legacy DIP sockets or wave-solder boards — no reflow profile to manage.
CTR range: 50% to 300% at 10 mA — designing the bias
The current transfer ratio spans 50% minimum to 300% maximum, both specified at a forward current of 10 mA. That wide spread means the circuit must be designed around the 50% floor to guarantee the output transistor saturates under worst-case temperature and aging. At the 10 mA bias point, a 50% CTR delivers 5 mA of collector current — enough to drive a logic gate input or a 5 V relay coil through a 1 kΩ pull-up with margin. The 300% ceiling is useful for low-power loops where you want to minimise LED drive current, but the designer should never rely on the high end for a production BOM.
Switching speed and output drive
Typical rise and fall times are 2.4 µs and 2.7 µs respectively, with turn-on and turn-off times of 5 µs and 3 µs.
The maximum forward current is 75 mA.