RXE050 Polymeric PTC Resettable Fuse Equivalent & Substitute Parts

Part Overview

The RXE050 is a polymeric PTC resettable fuse manufactured by Littelfuse Inc., rated for 72V maximum voltage with 500 mA hold current. This component is classified as obsolete, which necessitates identification of active equivalent and substitute parts for ongoing design support and procurement. The RXE050 belongs to the PolySwitch® RXE series and is designed for through-hole radial mounting in disc configuration.

Substiute Parts

RXE050

Littelfuse Inc.In Stock: 1017RXE050 Datasheet

Current PartRFQ

RXEF050

Littelfuse Inc.In Stock: 5249RXEF050 Datasheet

DirectRFQ

60R050XU

Littelfuse Inc.In Stock: 474260R050XU Datasheet

MFR RecommendedRFQ

0ZRC0050FF1E

Bel Fuse Inc.In Stock: 1025740ZRC0050FF1E Datasheet

DirectRFQ

MF-R050

Bourns Inc.In Stock: 1970MF-R050 Datasheet

DirectRFQ

PFRA.050

SCHURTER Inc.In Stock: 3066PFRA.050 Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the RXE050 is determined by the following critical electrical and mechanical parameters:

Electrical Compatibility Criteria:

• Voltage - Max: Must equal or exceed 72V
• Current - Hold (Ih) (Max): Must equal 500 mA
• Current - Trip (It): Must equal 1 A
• Current - Max: Must equal 40 A
• Time to Trip: Must equal 4 s
• Resistance - Initial (Ri) (Min): Must equal 500 mOhms (or 410 mOhms minimum for certain manufacturers)
• Resistance - Post Trip (R1) (Max): Must equal 1.17 Ohms

Mechanical Compatibility Criteria:

• Mounting Type: Through Hole
• Package / Case: Radial, Disc
• Lead Spacing: Tolerance within 0.199" to 0.201" (5.05mm to 5.10mm)

Compliance Criteria:

• RoHS Status: Active substitutes must be ROHS3 Compliant
• Product Status: Active preferred over obsolete

The substitute parts identified below meet these criteria with the following classifications:

• Direct Equivalent (Same Voltage Rating): RXEF050 (72V, Littelfuse)
• Voltage-Reduced Substitutes (60V Rating): 60R050XU (Littelfuse), MF-R050 (Bourns), PFRA.050 (SCHURTER)
• Voltage-Elevated Substitute (90V Rating): 0ZRC0050FF1E (Bel Fuse)

Parameter Comparison

Engineering Selection Recommendations

Primary Recommendation: RXEF050

The RXEF050 is the direct equivalent replacement for the RXE050. It maintains identical electrical specifications (72V, 500 mA hold current) and mechanical form factor (0.311" Dia x 0.118" T, 0.199" lead spacing). The RXEF050 is active in production status, ROHS3 compliant, and carries expanded approval certifications (CQC, CSA, TUV, UL). This part provides the highest compatibility with existing designs and should be the first choice for RXE050 replacement.

Secondary Recommendations: 60R050XU, MF-R050, PFRA.050

These three parts operate at 60V maximum voltage, which is 12V below the RXE050 specification. Selection of these parts is appropriate only when the circuit design operates at voltages not exceeding 60V. All three are active, ROHS3 compliant, and carry TUV certification. Mechanical dimensions are compatible with minor lead spacing tolerance variation (0.201" vs. 0.199"). The 60R050XU is manufactured by Littelfuse and maintains the same series continuity as the primary recommendation.

Alternative Recommendation: 0ZRC0050FF1E

The 0ZRC0050FF1E from Bel Fuse Inc. provides the highest voltage rating at 90V, exceeding the RXE050 specification by 18V. This part is suitable for applications requiring enhanced overvoltage margin. It is active in production, ROHS3 compliant, and carries AEC-Q200 automotive qualification. Lead spacing tolerance (0.201") is within acceptable mechanical compatibility range.

Compliance Consideration:

The RXE050 is RoHS non-compliant. All identified substitutes are ROHS3 compliant, making them suitable for new designs and applications subject to RoHS regulations.

Frequently Asked Questions (FAQ)

Q: Can RXEF050 be used as a direct drop-in replacement for RXE050?

A: Yes. The RXEF050 maintains identical electrical ratings (72V, 500 mA hold current, 1 A trip current, 4 s trip time) and mechanical dimensions (0.311" Dia x 0.118" T, 0.199" lead spacing). It is the direct equivalent part.

Q: What is the difference between RXE050 and RXEF050?

A: The primary differences are product status and compliance. RXE050 is obsolete and RoHS non-compliant. RXEF050 is active in production and ROHS3 compliant. Electrical and mechanical specifications are identical.

Q: Can 60R050XU, MF-R050, or PFRA.050 be used in place of RXE050?

A: These parts are electrically compatible only in circuits operating at 60V or below. The RXE050 is rated for 72V. If your circuit operates at 72V, these 60V-rated parts are not suitable. If your circuit operates at 60V or below, these parts are compatible substitutes.

Q: What is the significance of the lead spacing difference between 0.199" and 0.201"?

A: The lead spacing tolerance of 0.002" (0.05mm) is within standard PCB hole tolerance and does not prevent mechanical compatibility. Parts with 0.201" lead spacing can be mounted in PCBs designed for 0.199" spacing without functional impact.

Q: Why does 0ZRC0050FF1E have a 90V rating when RXE050 is 72V?

A: The 0ZRC0050FF1E is rated for higher voltage operation. It can be used in RXE050 applications as a substitute, providing additional overvoltage margin. The higher voltage rating does not prevent its use in 72V circuits.

Q: Are all substitute parts ROHS3 compliant?

A: Yes. All identified substitute parts (RXEF050, 60R050XU, 0ZRC0050FF1E, MF-R050, PFRA.050) are ROHS3 compliant. The original RXE050 is RoHS non-compliant.

Q: What certifications should I verify for my specific application?

A: Verify that the selected substitute part carries the required approval certifications for your application. RXEF050 carries CQC, CSA, TUV, and UL certifications. The 60V-rated parts (60R050XU, MF-R050, PFRA.050) carry cURus and TUV certifications. The 0ZRC0050FF1E carries cURus, TUV, and AEC-Q200 certifications.

Q: Can I use MF-R050 or PFRA.050 if my circuit is designed for 72V operation?

A: No. MF-R050 and PFRA.050 are rated for 60V maximum. Using them in a 72V circuit exceeds their voltage specification and may result in component failure or safety hazard.