Equivalent & Substitute Parts for 5MFP 1.25-R

Part Overview

The 5MFP 1.25-R is a 1.25 A, 250 V AC/DC fast-blow glass cartridge fuse manufactured by Bel Fuse Inc. in a 5mm x 20mm axial through-hole package. This component is actively produced and widely used in circuit protection applications requiring fast response characteristics. Equivalent and substitute parts are identified to support procurement flexibility, inventory management, and design continuity across manufacturing environments.

Substiute Parts

5MFP 1.25-R

Bel Fuse Inc.In Stock: 19475MFP 1.25-R Datasheet

Current PartRFQ

5SFP 1.25-R

Bel Fuse Inc.In Stock: 17595SFP 1.25-R Datasheet

Parametric EquivalentRFQ

02171.25MXEP

Littelfuse Inc.In Stock: 142602171.25MXEP Datasheet

SimilarRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility is determined by strict alignment of electrical and mechanical parameters. The following criteria establish valid equivalence:

Primary Substitution Criteria:

• Current Rating: 1.25 A (exact match required)
• Voltage Rating (AC): 250 V (exact match required)
• Fuse Type: Cartridge, Glass (exact match required)
• Response Time: Fast Blow (exact match required)
• Package / Case: 5mm x 20mm (Axial) (exact match required)
• Mounting Type: Through Hole (exact match required)
• Operating Temperature Range: -55°C to 125°C (exact match required)

Secondary Considerations:

• Breaking Capacity and Melting I²t values may vary within acceptable engineering tolerances
• DC Cold Resistance variations are acceptable within normal manufacturing specifications
• Approval Agency certifications must include relevant regional standards for the application

All identified substitutes meet these criteria and are suitable for direct component replacement in equivalent circuit protection applications.

Parameter Comparison

Engineering Selection Recommendations

All three parts are actively produced and ROHS3 compliant, meeting current environmental and regulatory requirements. Selection between these substitutes should be based on the following factors:

5MFP 1.25-R (Bel Fuse Inc.): Primary specification with highest breaking capacity (200 A). Suitable for applications requiring maximum fault current handling capability.

5SFP 1.25-R (Bel Fuse Inc.): Parametric equivalent with lower breaking capacity (35 A) and higher melting I²t (2.5). Offers broader approval agency coverage including CCC, IMQ, SEMKO, and VDE certifications. Lower DC cold resistance (0.062 Ohms) may be advantageous in low-resistance circuit applications.

02171.25MXEP (Littelfuse Inc.): Cross-manufacturer equivalent with comprehensive international certifications (BSI, CE, CCC, CSA, KC, PSE, SEMKO, UR, VDE). Melting I²t of 2.23 provides intermediate thermal response. Slightly larger physical dimensions (5.80mm x 22.50mm) require verification of mechanical fit in existing PCB footprints.

All parts maintain identical electrical performance for standard 1.25 A, 250 V AC/DC circuit protection applications.

Frequently Asked Questions (FAQ)

Q: Can 5SFP 1.25-R replace 5MFP 1.25-R in all applications?

A: Yes, for standard circuit protection applications. Both parts share identical current rating, voltage rating, response time, and package specifications. The 5MFP has higher breaking capacity (200 A vs. 35 A); applications requiring this higher fault current handling should retain the 5MFP specification.

Q: What is the significance of the different Breaking Capacity values?

A: Breaking capacity indicates the maximum fault current the fuse can safely interrupt. The 5MFP 1.25-R (200 A) is rated for higher fault currents than 5SFP 1.25-R and 02171.25MXEP (both 35 A). Select based on the maximum prospective short-circuit current in your circuit.

Q: Are there physical fit differences between these parts?

A: The 02171.25MXEP has slightly larger dimensions (5.80mm x 22.50mm) compared to the standard 5mm x 20mm specification. Verify PCB footprint and holder clearances before substitution to ensure mechanical compatibility.

Q: Which part has the best international certification coverage?

A: The 02171.25MXEP (Littelfuse) carries the broadest approval agency list: BSI, CE, CCC, CSA, KC, PSE, SEMKO, UR, and VDE. Select this part for applications requiring specific regional compliance certifications.

Q: Do these parts have different DC cold resistance values?

A: Yes. The 5MFP has 0.09 Ohms, while 5SFP has 0.062 Ohms and 02171.25MXEP has 0.0701 Ohms. In low-resistance circuits or high-current applications, lower resistance values may reduce voltage drop and heat generation.

Q: Are all parts RoHS compliant?

A: Yes, all three parts are ROHS3 compliant and suitable for applications requiring environmental compliance.