4N26TM

Overview

The 4N26TM is a high-speed optocoupler manufactured by onsemi, featuring an infrared-emitting GaAs LED coupled to a silicon NPN phototransistor with a built-in base terminal. This component provides electrical isolation of 7500 Vrms between input and output circuits. It is housed in a standard 6-pin DIP package, designed for robust signal transmission in environments requiring galvanic isolation.

Feature Summary

• Integrated base terminal on the phototransistor allows for adjustable switching speed and improved noise immunity
• High isolation voltage rating ensures safe operation in high-voltage industrial applications
• Infrared LED emitter paired with silicon phototransistor for reliable optical coupling

Applications

• Industrial automation control systems
• Power supply feedback loops
• Microprocessor system interface isolation

Procurement Notes

Verify the specific suffix 'TM' against the official datasheet to confirm pinout and packaging dimensions match your PCB layout requirements. Ensure the component meets the required isolation voltage standards for your specific safety certification needs before finalizing procurement.

Selection Notes

Select this component when a dedicated base terminal is needed to optimize switching times or reduce sensitivity to noise. Consider the 6-DIP package constraints and verify that the current transfer ratio meets the drive requirements of the downstream circuitry.

Part Context

This device belongs to the family of general-purpose optocouplers used for isolating low-voltage digital signals from higher-voltage analog or power circuits. The inclusion of a base connection distinguishes it from simpler two-terminal optoisolators, offering greater design flexibility for timing adjustments.

Replacement Considerations

Check for direct pin-compatible alternatives such as the 4N25 or 4N27 series if availability is constrained, ensuring that the collector-emitter voltage and isolation ratings remain compatible with the original design specifications.