4N25

Overview

The Lite-On 4N25 is a general-purpose optocoupler featuring a single channel with a GaAs infrared LED optically coupled to an NPN silicon phototransistor. It provides electrical isolation with a maximum isolation voltage of 2500Vrms and operates within a temperature range of -55°C to 100°C. The device supports a maximum forward current of 80mA and a typical current transfer ratio of 20%. Switching characteristics include a typical rise time of 3μs and a fall time of 3μs, with a maximum collector-emitter voltage of 30V.

Feature Summary

• Integrates an infrared emitting diode with an NPN phototransistor for signal transmission
• Provides high-voltage electrical isolation between input and output circuits
• Designed for general-purpose applications requiring standard switching speeds

Applications

• General-purpose signal isolation in electronic circuits
• Interface circuits for logic systems
• Switching power supply feedback loops

Procurement Notes

Verify the specific suffix (e.g., S, TA1) against official datasheets to confirm package type and certification status. Confirm availability as distribution channels may list this component as temporarily unavailable or discontinued. Ensure the selected variant matches the required isolation voltage and operating temperature specifications for the target application environment.

Selection Notes

Select the 4N25 for applications requiring basic galvanic isolation with moderate speed requirements. Consider the 6-pin DIP or surface mount variants based on PCB layout constraints. Verify that the 20% minimum current transfer ratio meets the drive requirements of the downstream load. Check for necessary safety certifications such as UL or VDE if the end product requires regulatory compliance.

Part Context

The 4N25 belongs to the widely recognized 4N25 series of optocouplers manufactured by Lite-On Inc. This series is established for general-purpose use, offering a balance of performance and cost-effectiveness. The component serves as a fundamental building block for isolating low-voltage control signals from higher-voltage power stages in various industrial and consumer electronics.

Replacement Considerations

Compatible substitutes include the LTV-4N25 from Lite-On and the 4N25M from onsemi. When replacing, verify that the alternative part maintains equivalent isolation voltage, pinout configuration, and switching times to ensure circuit compatibility without redesign.