FOD785A

Overview

The FOD785A is a single-channel transistor output optocoupler manufactured by onsemi. It features an NPN phototransistor output with a maximum collector-emitter voltage of 80 V and a continuous collector current of 50 mA. The device provides 5000 Vrms insulation voltage for robust signal isolation. Key electrical parameters include a forward voltage of 1.4 V at 50 mA forward current, and a current transfer ratio ranging from 80% to 160%. Switching characteristics specify rise and fall times of 18 µs each. The component operates within a temperature range of -55°C to +110°C and dissipates up to 100 mW of power.

Feature Summary

• Provides high-voltage electrical isolation between input and output circuits using optical coupling technology.
• Utilizes an NPN phototransistor output stage capable of handling significant collector currents for driving loads.
• Designed for reliable operation across extended industrial temperature ranges.

Applications

• General-purpose digital signal isolation in industrial control systems
• Interface circuits for microcontrollers and logic families requiring galvanic separation
• Power supply feedback loops for voltage regulation and monitoring

Procurement Notes

Verify the specific package variant when ordering, as the base part number may correspond to different packaging options such as DIP or surface-mount reels. Confirm RoHS compliance status directly with the manufacturer or authorized distributors, as regulatory markings can vary by production batch. Ensure that the selected supplier provides valid traceability documentation for quality assurance purposes in critical applications.

Selection Notes

Select this component when a single channel of moderate-speed isolation is required with a phototransistor output interface. Consider the 80 V collector-emitter voltage rating to ensure compatibility with downstream circuit loads. Evaluate the 18 µs switching speed against system timing requirements to confirm adequate performance for the intended data rate or pulse width modulation frequency.

Part Context

This component belongs to the FOD785 series of transistor output optocouplers from onsemi. The series is designed for general-purpose isolation applications where cost-effective and reliable signal transmission is necessary. It serves as a standard solution for breaking ground loops and protecting sensitive electronics from high-voltage transients in various electronic assemblies.

Replacement Considerations

Compatible alternatives include the FOD785ASD for surface-mount applications within the same family. Verify pinout compatibility and electrical parameter equivalence before substituting other brands' transistor output optocouplers to ensure functional interchangeability.