Isolation and signal transfer for industrial I/O
The onsemi H11A617B300 is a single-channel transistor-output optocoupler in a 4-DIP through-hole package, designed to pass a DC logic-level signal across a 5300Vrms galvanic isolation barrier. With a current transfer ratio (CTR) guaranteed between 63% and 125% at a 10 mA forward current, the output transistor saturates reliably at a Vce of 400 mV max — the CTR band tells you the LED drive current needed to guarantee a logic-low at the receiver side.
Parametric boundaries for BOM fit
The output side handles up to 70 V and 50 mA continuous — enough to drive a PLC digital input or a low-current relay coil directly, but not a motor contactor. Typical rise and fall times of 2.4 µs each set the data rate ceiling around 200 kbps; for faster serial buses like RS-485 you would need a logic-output optocoupler. The full military temperature range of -55°C to 100°C means this part can sit in an outdoor telecom cabinet or an engine-bay ECU without derating.
No pin-compatible drop-in replacement is documented by the manufacturer, so a BOM change may require a board spin or a parametric search for a similar 4-DIP transistor-output optocoupler.