RXEF040-1 Polymeric PTC Resettable Fuse Equivalent & Substitute Parts

Part Overview

The RXEF040-1 is a polymeric PTC resettable fuse manufactured by Littelfuse Inc., rated for 72V maximum voltage with 400 mA hold current. This component is designed for overcurrent protection in electronic circuits and automatically resets after a fault condition is cleared. The RXEF040-1 is currently listed as obsolete, making identification of active equivalent parts essential for ongoing design support and procurement.

Substiute Parts

RXEF040-1

Littelfuse Inc.In Stock: 781RXEF040-1 Datasheet

Current PartRFQ

RXEF040

LittelfuseIn Stock: 2349RXEF040 Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the RXEF040-1 is determined by strict equivalence across the following critical parameters:

• Voltage rating: 72V maximum
• Current hold specification: 400 mA
• Current trip specification: 800 mA
• Mounting configuration: Through Hole Radial, Disc
• Physical dimensions: 0.299" Dia x 0.118" T with 0.199" lead spacing
• Thermal operating range: -40°C ~ 85°C
• Regulatory compliance: CQC, CSA, TUV, UL certifications

The RXEF040 meets all substitution criteria as an active product variant within the same PolySwitch® RXEF series, maintaining identical electrical and mechanical specifications.

Parameter Comparison

Engineering Selection Recommendations

The RXEF040 is the direct active equivalent for the obsolete RXEF040-1. Both components are manufactured by Littelfuse within the PolySwitch® RXEF series and maintain identical electrical performance and mechanical specifications. The RXEF040 carries active product status with current manufacturing support and availability. Both variants maintain full compliance with CQC, CSA, TUV, and UL certifications, and both are ROHS3 compliant. The primary distinction is product lifecycle status: RXEF040-1 is obsolete while RXEF040 is actively produced. For new designs and ongoing procurement, the RXEF040 is the appropriate selection.

Frequently Asked Questions (FAQ)

Q: Can RXEF040 directly replace RXEF040-1 in existing designs?

A: Yes. The RXEF040 is electrically and mechanically identical to RXEF040-1. All electrical parameters, including voltage rating, current hold, current trip, resistance characteristics, and thermal operating range are equivalent. Physical dimensions and lead spacing are identical, ensuring direct PCB compatibility.

Q: What is the difference between RXEF040-1 and RXEF040?

A: The primary difference is product status. RXEF040-1 is obsolete and no longer manufactured. RXEF040 is the active equivalent with current manufacturing support. All technical specifications are identical.

Q: Are there packaging differences between these parts?

A: RXEF040-1 is specified with radial disc packaging. RXEF040 is specified with bag packaging. Both use identical through-hole radial disc form factors with matching lead spacing and dimensions.

Q: Do both parts meet the same regulatory certifications?

A: Yes. Both RXEF040-1 and RXEF040 carry CQC, CSA, TUV, and UL approvals. Both are ROHS3 compliant and REACH unaffected.

Q: What is the lead spacing for these components?

A: Both components have a lead spacing of 0.199" (5.05mm), ensuring compatibility with standard through-hole PCB layouts designed for the RXEF series.