4N39

Overview

The onsemi 4N39 is a single-channel optoisolator featuring an infrared LED emitter paired with a silicon-controlled rectifier (SCR) output. It provides electrical isolation between input and output circuits, rated at 5300 Vrms. The device is housed in a standard 6-pin dual in-line package (DIP-6). This configuration allows for the control of AC loads via the SCR output while maintaining galvanic separation.

Feature Summary

• Integrates an infrared emitting diode with a silicon-controlled rectifier output stage within a single encapsulated unit.
• Provides high-voltage electrical isolation capability between the input control circuit and the output load circuit.
• Designed specifically for applications requiring latching operation characteristics inherent to SCR technology.

Applications

• Triggering AC loads that require latching operation
• Industrial control systems requiring isolated switching
• General purpose optoisolation for SCR gate drive

Procurement Notes

Verify the specific ordering suffix against the manufacturer's current datasheet to ensure the correct package variant and tape/reel or tube packaging options are selected. Confirm that the 5300 Vrms isolation rating meets the system's safety requirements. Check for any recent updates to the RoHS compliance status or lead-free specifications before finalizing procurement orders.

Selection Notes

Select this component when an isolated switch with latching behavior is required rather than a simple on/off transistor switch. Consider the forward voltage drop and holding current requirements of the SCR output relative to the load being driven. Ensure the input LED current limits are respected to maintain adequate isolation performance and longevity under expected operating temperatures.

Part Context

The 4N39 belongs to the family of photo-SCR optoisolators manufactured by onsemi. Unlike photo-transistor or photo-triac variants, this device utilizes a silicon-controlled rectifier structure. It is distinct from other 4N series devices such as the 4N25 or 4N26 which utilize different output technologies like Darlington pairs or standard transistors.

Replacement Considerations

• 4N40

FAQ

What type of output device does the 4N39 use?

The 4N39 uses a Silicon-Controlled Rectifier (SCR) as its output device, which is suitable for triggering AC loads.

What is the isolation voltage rating of the 4N39?

The device provides an isolation voltage rating of 5300 Vrms between the input LED and the output SCR.