4170Vrms isolation with Darlington gain
The onsemi TIL113M is a single-channel DC-input optoisolator with a Darlington transistor output that includes a base terminal. The 4170Vrms isolation rating means this part provides reinforced galvanic isolation between the input LED and the output phototransistor pair, suitable for breaking ground loops and protecting low-voltage logic from high-side transients in industrial control interfaces. This gain margin means a 5 V logic signal driving the LED can switch a 24 V PLC input module or a small relay coil without an external buffer transistor.
Switching speed and output drive limits
Turn-on time is 5 µs typical, but turn-off stretches to 100 µs max — the Darlington's stored base charge takes that long to clear. This asymmetry sets the practical switching ceiling below 5 kHz; for higher-speed isolation (serial data, PWM gate drive), a phototransistor or logic-output optocoupler is a better fit. The output transistor is rated for 30 V maximum collector-emitter, and the LED forward voltage is 1.2 V typical at 10 mA with an absolute maximum forward current of 80 mA. The 6-DIP package with 0.300-inch row spacing is a standard through-hole footprint that mates with sockets or wave-solder processes.