Littelfuse 0451005.MRL Surface Mount Board Mount Fuse Equivalent & Substitute Parts

Part Overview

The Littelfuse 0451005.MRL is a 5 A, 125 V AC/DC surface mount board mount fuse in the NANO²® 451 series. This fast-blow fuse is designed for circuit protection in applications requiring compact 2-SMD, square end block packaging. The part is active in production with extensive inventory availability. Substitute parts are identified based on matching electrical ratings, mechanical dimensions, and functional performance characteristics to ensure direct board-level compatibility.

Substiute Parts

0451005.MRL

Littelfuse Inc.In Stock: 1051320451005.MRL Datasheet

Current PartRFQ

0448005.MR

Littelfuse Inc.In Stock: 407320448005.MR Datasheet

Parametric EquivalentRFQ

0451005.MRSN

Littelfuse Inc.In Stock: 29350451005.MRSN Datasheet

Parametric EquivalentRFQ

0451005.NRL

Littelfuse Inc.In Stock: 35340451005.NRL Datasheet

Parametric EquivalentRFQ

0453005.MR

Littelfuse Inc.In Stock: 260950453005.MR Datasheet

Parametric EquivalentRFQ

CB61F5A-TR1

Eaton - Electronics DivisionIn Stock: 1927CB61F5A-TR1 Datasheet

DirectRFQ

SF-2410FP500T-2

Bourns Inc.In Stock: 6809SF-2410FP500T-2 Datasheet

DirectRFQ

SF-2410HI500T-2

Bourns Inc.In Stock: 5775SF-2410HI500T-2 Datasheet

DirectRFQ

3404.0017.11

SCHURTER Inc.In Stock: 31983404.0017.11 Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitute parts are classified into three categories based on substitution relationship type:

Parametric Equivalents (Littelfuse NANO²® series): Parts 0448005.MR, 0451005.MRSN, 0451005.NRL, and 0453005.MR share identical electrical ratings (5 A, 125 V AC/DC), response time (fast blow), package type (2-SMD, square end block), and physical dimensions. These parts differ in packaging format (tape & reel vs. cut tape) and series designation within the Littelfuse product line. Parametric equivalents maintain the same melting I²t value (5.566) except for 0448005.MR (4.49), which represents a different thermal response profile but remains functionally compatible for the specified electrical parameters.

Direct Equivalents (Cross-manufacturer): Parts CB61F5A-TR1 (Eaton), SF-2410FP500T-2 and SF-2410HI500T-2 (Bourns), and 3404.0017.11 (SCHURTER) meet the core electrical and mechanical requirements. These parts are from different manufacturers and may have variations in breaking capacity, melting I²t, and physical dimensions within acceptable tolerances. All maintain 5 A current rating, 125 V AC/DC voltage rating, fast-blow response, and 2-SMD surface mount configuration.

Key Parameters for Substitution Eligibility:

• Current Rating: 5 A (mandatory match)
• Voltage Rating: 125 V AC and 125 V DC (mandatory match)
• Response Time: Fast Blow (mandatory match)
• Package / Case: 2-SMD, Square End Block (mandatory match)
• Mounting Type: Surface Mount (mandatory match)
• Physical Dimensions: 0.240" L nominal (all substitutes within tolerance)

Parameter Comparison

Engineering Selection Recommendations

All listed substitute parts maintain active product status and meet the core electrical specifications (5 A, 125 V AC/DC, fast-blow response, surface mount 2-SMD configuration). Selection should be based on the following criteria:

Littelfuse NANO²® Series (0448005.MR, 0451005.MRSN, 0451005.NRL, 0453005.MR): These parts provide the highest compatibility with the original 0451005.MRL due to identical electrical ratings and thermal characteristics. The 0451005.MRSN and 0451005.NRL variants offer different regional approval certifications (METI, UR) suitable for specific geographic markets. The 0453005.MR provides the largest inventory (25,998 pcs) among Littelfuse options and carries CSA, PSE, and UL approvals matching the original part.

Eaton CB61F5A-TR1: This part offers higher breaking capacity (100 A AC, 300 A DC) compared to the 50 A rating of the original part. It carries cULus and PSE certifications and is suitable for applications requiring enhanced fault protection margins. Physical dimensions are within tolerance (0.240" L x 0.101" W x 0.101" H).

Bourns SingleFuse™ Series (SF-2410FP500T-2, SF-2410HI500T-2): Both Bourns parts maintain identical electrical ratings and 50 A breaking capacity. The SF-2410FP500T-2 provides a melting I²t of 6.175, while the SF-2410HI500T-2 offers significantly higher I²t (50.308) for applications requiring slower thermal response. Both carry cUL and UL certifications.

SCHURTER 3404.0017.11: This part differs in package configuration (2-SMD, J-Lead vs. square end block) and has the lowest melting I²t (2.9), indicating faster thermal response. It carries cURus certification and is available in bulk packaging. Physical dimensions are larger (0.291" L x 0.122" W x 0.102" H), which may affect board layout compatibility.

Frequently Asked Questions (FAQ)

Q: Can I substitute the 0451005.MRL with any of the listed parts without design changes?

A: Littelfuse NANO²® series parts (0448005.MR, 0451005.MRSN, 0451005.NRL, 0453005.MR) are direct substitutes with identical electrical ratings and physical dimensions. Cross-manufacturer parts (Eaton, Bourns, SCHURTER) are electrically compatible but may require PCB layout verification due to minor dimensional variations and different package lead styles.

Q: What is the difference between the Littelfuse 0451005.MRL and 0448005.MR?

A: Both parts share identical electrical ratings (5 A, 125 V AC/DC) and physical dimensions. The primary difference is the melting I²t value: 0451005.MRL has 5.566 while 0448005.MR has 4.49, indicating faster thermal response in the 0448005.MR. The 0451005.MRL is supplied in cut tape format, while 0448005.MR is supplied in tape & reel format.

Q: Why does the SCHURTER 3404.0017.11 have a different package designation (J-Lead vs. square end block)?

A: The SCHURTER part uses J-Lead termination style instead of square end block. While electrically equivalent, this difference affects PCB footprint and soldering characteristics. Verify PCB design compatibility before substitution.

Q: What is the significance of the melting I²t parameter in fuse selection?

A: Melting I²t determines the thermal response time of the fuse. Lower I²t values indicate faster thermal response, while higher values indicate slower response. The original 0451005.MRL has an I²t of 5.566. Substitutes with significantly different I²t values (such as SF-2410HI500T-2 at 50.308 or 3404.0017.11 at 2.9) may alter circuit protection timing and should be selected based on specific application requirements.

Q: Are all substitute parts RoHS3 compliant?

A: All listed substitute parts are RoHS3 compliant. The original 0451005.MRL and most substitutes are REACH unaffected, except for 0453005.MR and SF-2410HI500T-2, which are REACH affected.

Q: Which substitute part has the highest inventory availability?

A: The Littelfuse 0453005.MR has the highest inventory among substitutes with 25,998 pcs in stock, followed by the original 0451005.MRL with 105,034 pcs.

Q: Can I use the Bourns SF-2410HI500T-2 if I need a slower fuse response?

A: Yes. The SF-2410HI500T-2 has a melting I²t of 50.308, significantly higher than the original part's 5.566, providing slower thermal response. This part is suitable for applications requiring extended response time before fuse activation.