ONSEMI FOD817 Transistor Output Optocoupler, 1 Channel, DIP, 4-Pin, 50% CTR

The ONSEMI FOD817 is a high-reliability, single-channel optocoupler designed for robust isolation and signal transfer in demanding electronic circuits. It features a gallium arsenide infrared emitting diode optically coupled to a silicon phototransistor, providing excellent electrical isolation and noise immunity. This makes it particularly suitable for interfacing digital logic and microprocessor inputs with higher voltage or noisy power sections, ensuring clean and safe signal transmission.

A key specification is its high isolation voltage of 5kV, which provides a substantial safety barrier between input and output, protecting sensitive control circuitry. The device is guaranteed for a minimum current transfer ratio (CTR) of 50%, ensuring efficient signal coupling. With a continuous forward current rating of 50mA and a broad operating temperature range from -55°C to +110°C, it is built for high-performance applications in challenging environments.

The component comes in a standard 4-pin DIP (Dual In-line Package) format, making it compatible with through-hole PCB assembly and easy to prototype with. It is also fully applicable for lead-free infrared (IR) reflow soldering processes, complying with modern manufacturing standards. The minimum collector-emitter voltage (BVCEO) is guaranteed at 70V, providing a reliable buffer for the output stage.

Primary Applications

• Power Management Systems: Used for feedback isolation in switch-mode power supplies (SMPS), inverters, and motor drives.
• Digital Logic Interface: Provides voltage level shifting and noise isolation for microcontroller and digital I/O lines.
• Industrial Controls: Ideal for PLCs, sensor interfaces, and relay driving where electrical isolation is critical.
• Communication Systems: Isolates signal lines in data acquisition and telecommunication equipment.