5 kV Darlington optocoupler for industrial isolation
The FOD852S is a single-channel Darlington-output optocoupler from onsemi, rated for 5000Vrms isolation — enough for reinforced galvanic barriers in motor drives, industrial PSU feedback, and PLC digital I/O modules. Its Darlington output delivers a current transfer ratio (CTR) of 1000% minimum and up to 15000% maximum at a forward current of 1 mA, which means a low-side MCU pin can drive the LED directly and still switch a 150 mA load on the output side.
Output voltage and switching speed for load interface
The output transistor can block up to 300 V, so the FOD852S can drive relays, solenoids, or small DC loads on a 24 V or 48 V bus without a secondary driver transistor. Typical rise time is 100 µs and fall time 20 µs — adequate for 50/60 Hz line-synchronous switching or slow digital signals, but not for high-speed data or PWM above a few hundred hertz.
Active production, ROHS3, surface-mount package
Packaged in a 4-SMD Gull Wing body — the leads are surface-mount compatible with standard reflow profiles. The supplier device package is 4-SMD. Supplied in tube.
Temperature range and storage considerations
Rated for -30°C to +100°C operating ambient — suitable for industrial enclosures, outdoor telecom cabinets, and factory-floor equipment that sees moderate temperature swings. The 4-SMD Gull Wing package is moisture-sensitive; store the reels dry per the MSL label on the tube. If the tube has been opened, bake per IPC/JEDEC J-STD-033 before reflow.