AC/DC-to-logic interface optocoupler — 2500 Vrms isolation
The onsemi HCPL3700SV is a single-channel optocoupler that accepts both AC and DC input signals and outputs a logic-level signal via a Darlington transistor pair. The 2500 Vrms isolation rating means this part provides galvanic isolation between a high-voltage AC or DC field side and a low-voltage logic controller, protecting the control board from transients and ground loops. Rated for continuous operation from -40°C to 85°C, it suits industrial environments where the optocoupler sits on a PCB inside a panel exposed to temperature swings. The 8-SMD gull-wing package with a surface-mount footprint keeps the assembly compatible with reflow soldering.
Switching response and output drive
Typical turn-on time is 6 µs and turn-off is 25 µs, with rise and fall times of 45 µs and 0.5 µs respectively. The 20 V maximum output rating gives headroom for 12 V or 15 V logic rails. The AC/DC input stage means the LED side accepts a rectified waveform — no external bridge diode needed for AC sensing applications like zero-cross detection or mains monitoring.
onsemi has marked the HCPL3700SV as obsolete. No official successor or pin-compatible replacement is recorded from the original manufacturer. For a BOM that requires this exact order code, the only sourcing path is the open market. No stock-holding claim is made here — each lot is sourced per request.