RKEF400-2

Ptc Resettable Fuses Overview

The Littelfuse RKEF400-2 is a PolySwitch resettable PPTC fuse from the RKEF series, designed for through-hole PCB mounting. It features a maximum voltage rating of 60 VDC and a hold current of 4 A. The trip current is specified at 8 A with a typical trip time of 24 seconds. Initial resistance ranges from a minimum of 14 mΩ to a maximum post-trip resistance of 60 mΩ. The device supports a maximum fault current of 40 A and operates within a temperature range of -40°C to 85°C, with a power dissipation rating of 3.7 W.

Ptc Resettable Fuses Feature Summary

• Provides overcurrent protection via positive temperature coefficient polymer technology that resets automatically after fault clearance.
• Offers high surge capability with a maximum fault current rating of 40 A to withstand transient energy events.
• Features radial leaded construction suitable for standard through-hole printed circuit board assembly processes.

Ptc Resettable Fuses Applications

• Overcurrent protection for portable electronic devices
• Protection circuits in automotive electronics systems
• Power supply input filtering and safeguarding
• Interface port protection in consumer hardware

Ptc Resettable Fuses Procurement Notes

Verify the specific ordering suffix against the manufacturer's official documentation to ensure correct packaging configuration and mechanical dimensions. Confirm that the required hold and trip currents align precisely with the system design parameters before finalizing procurement orders to avoid performance mismatches.

Ptc Resettable Fuses Selection Notes

Select this component when a 60 VDC rating and 4 A continuous current capacity are required for circuit protection. Ensure the application environment remains within the specified -40°C to 85°C operating temperature range. Consider the 3.7 W power dissipation limit during normal operation to maintain thermal stability and reliable long-term performance.

Ptc Resettable Fuses Part Context

This part belongs to the Littelfuse PolySwitch RKEF series of resettable fuses. These components utilize proprietary polymer technology to provide reusable overcurrent protection. The series is engineered for high reliability in demanding environments, offering a cost-effective alternative to traditional one-time fuses in various industrial and commercial applications.

Ptc Resettable Fuses Replacement Considerations

Publicly confirmed substitute part numbers are not available in the provided source data. Verify compatibility with any potential alternatives by cross-referencing electrical ratings, package dimensions, and thermal characteristics with the original specifications.