RXEF135-AP Polymeric PTC Resettable Fuse - Equivalent & Substitute Parts

Part Overview

The RXEF135-AP is a polymeric PTC resettable fuse manufactured by Littelfuse Inc. in the PolySwitch® RXEF series. This component is rated for 72V maximum voltage with a 1.35A hold current and is designed for through-hole radial mounting in disc configuration. The part is currently active in production with 2021 units in stock. Substitute parts are identified when electrical specifications, mechanical compatibility, and regulatory compliance align with the original component, enabling direct replacement in circuit applications without design modification.

Substiute Parts

RXEF135-AP

Littelfuse Inc.In Stock: 2047RXEF135-AP Datasheet

Current PartRFQ

72R135XMR

Littelfuse Inc.In Stock: 214772R135XMR Datasheet

DirectRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the RXEF135-AP is determined by strict equivalence across the following critical parameters:

Electrical specifications must match exactly: 72V maximum voltage, 1.35A hold current, 2.7A trip current, 9.6s time to trip, 120 mOhms minimum initial resistance, and 300 mOhms maximum post-trip resistance. These parameters define the protective function and circuit behavior of the polymeric PTC resettable fuse.

Mechanical compatibility requires identical mounting type (through hole), package configuration (radial disc), and lead spacing within tolerance to ensure proper PCB assembly and thermal performance.

Regulatory compliance must include ROHS3 certification as a minimum requirement. Additional certifications (CQC, CSA, TUV, UL) enhance suitability but are not mandatory for substitution.

The 72R135XMR from Littelfuse Inc. meets all electrical and mechanical criteria for direct substitution with the RXEF135-AP.

Parameter Comparison

Engineering Selection Recommendations

The 72R135XMR is a direct substitute for the RXEF135-AP based on complete electrical and mechanical equivalence. Both components are manufactured by Littelfuse Inc., share identical electrical ratings across all critical parameters, and are configured for through-hole radial disc mounting with compatible lead spacing.

Both parts maintain ROHS3 compliance and are certified by independent regulatory bodies. The RXEF135-AP carries broader certification coverage (CQC, CSA, TUV, UL), while the 72R135XMR holds cURus and TUV certifications. Selection between these parts should be based on application-specific certification requirements and inventory availability rather than electrical or mechanical performance differences.

Frequently Asked Questions (FAQ)

Q: Can the 72R135XMR replace the RXEF135-AP in existing designs?

A: Yes. The 72R135XMR is electrically and mechanically equivalent to the RXEF135-AP. All critical parameters including voltage rating, hold current, trip current, and resistance specifications are identical. Lead spacing is compatible within standard PCB assembly tolerances.

Q: Are there differences in regulatory certifications between these parts?

A: The RXEF135-AP holds CQC, CSA, TUV, and UL certifications. The 72R135XMR holds cURus and TUV certifications. Both meet ROHS3 compliance. Selection should align with application-specific certification requirements.

Q: What is the significance of the lead spacing difference (5.08mm vs 5.10mm)?

A: The 0.02mm difference in lead spacing is within standard PCB manufacturing tolerances and does not affect mechanical compatibility or assembly feasibility for through-hole radial disc components.

Q: Are these parts from the same manufacturer?

A: Yes. Both the RXEF135-AP and 72R135XMR are manufactured by Littelfuse Inc., ensuring consistent quality and performance standards.

Q: What parameters must match for substitution eligibility?

A: Voltage rating, hold current, trip current, time to trip, initial and post-trip resistance, operating temperature range, mounting type, and package configuration must be identical. Lead spacing must be compatible within assembly tolerances.