RXEF040S

Ptc Resettable Fuses Overview

The Littelfuse RXEF040S is a PolySwitch radial leaded PPTC resettable fuse designed for overcurrent protection. It features a hold current of 400 mA and a trip current of 800 mA, with a maximum voltage rating of 72 VDC. The device has a maximum fault current rating of 40 A and an initial resistance of 1.29 Ohms. Operating within a temperature range of -40°C to +85°C, it utilizes a radial leaded package with a 5.8 mm lead spacing. The component measures 7.6 mm in diameter and 3 mm in length, dissipating up to 560 mW.

Ptc Resettable Fuses Feature Summary

• Provides automatic circuit recovery after fault conditions clear without manual replacement
• Offers high interrupting capacity suitable for protecting against short circuits
• Compatible with standard through-hole PCB assembly processes

Ptc Resettable Fuses Applications

• Computer motherboards
• USB hubs, ports and peripherals
• Industrial controls

Ptc Resettable Fuses Procurement Notes

Verify the specific suffix 'S' corresponds to the bulk packaging configuration rather than tape-and-reel variants when sourcing. Confirm RoHS compliance status via the manufacturer's latest documentation, as regulatory updates may affect material declarations. Ensure the selected distributor provides valid UL and TUV certification records for the specific batch to meet end-product safety requirements.

Ptc Resettable Fuses Selection Notes

Select this component for circuits requiring a 400 mA holding current with a 72 VDC maximum operating voltage. The radial lead form factor is appropriate for applications where surface-mount space is constrained but through-hole reliability is preferred. Evaluate the 1.29 Ohm resistance impact on signal integrity or power loss in low-voltage sensitive lines before finalizing the design.

Ptc Resettable Fuses Part Context

This part belongs to the RXEF series of PolySwitch resettable fuses from Littelfuse. The series is characterized by low hold currents and high voltage ratings, offering a comprehensive solution for overcurrent protection in compact electronic designs. It serves as a solid-state alternative to traditional single-use fuses in various consumer and industrial electronics.

Ptc Resettable Fuses Replacement Considerations

The RXEF040 is a parameter-equivalent substitute within the same product family. Verify that the physical dimensions and lead spacing of the alternative match the existing PCB footprint to ensure mechanical compatibility during installation.

Ptc Resettable Fuses FAQ

What is the maximum fault current rating for the RXEF040S?

The maximum fault current rating is 40 A.

Does the RXEF040S require manual resetting after a trip event?

No, it is a resettable device that automatically returns to its low-resistance state once the fault condition is removed and the component cools down.