RUE400

Ptc Resettable Fuses Overview

The Littelfuse RUE400 is a PolySwitch resettable PTC fuse rated for 30 VDC maximum voltage and 4 A hold current. It features an 8 A trip current and a maximum fault current rating of 40 A. The device has a typical resistance of 50 mOhms and trips in 12.7 seconds. Operating temperature ranges from -40°C to +85°C. Dimensions are 19.3 mm length, 14 mm width, and 3 mm height with a 5.10 mm lead spacing.

Ptc Resettable Fuses Feature Summary

• Polymeric self-resetting circuit protection mechanism
• Radial through-hole mounting configuration
• High fault current tolerance up to 40 A

Ptc Resettable Fuses Applications

• Overcurrent protection for portable electronics
• Protection of battery-powered devices
• Circuit safeguarding in telecommunications equipment

Ptc Resettable Fuses Procurement Notes

This component is officially classified as obsolete and no longer manufactured by Littelfuse. Procurement should focus on verified direct substitutes such as the RUEF400 series. Verify datasheet revisions and physical compatibility before integration into new designs.

Ptc Resettable Fuses Selection Notes

Designers must account for the discontinued status when selecting this part. The RUEF400 serves as the primary functional equivalent within the same family. Ensure that thermal derating curves and package dimensions of the substitute match the original application requirements.

Ptc Resettable Fuses Part Context

The RUE400 belongs to the PolySwitch RUEF series of resettable fuses. These components utilize polymer positive temperature coefficient technology to provide automatic circuit protection. The series is designed for applications requiring reliable overcurrent interruption without manual replacement.

Ptc Resettable Fuses Replacement Considerations

The RUEF400 is listed as a direct substitute for the RUE400. Verify that the substitute meets all electrical ratings including hold current, trip current, and maximum voltage specifications.