Littelfuse 0451.062MRSN Surface Mount Board Fuse Equivalent & Substitute Parts

Part Overview

The Littelfuse 0451.062MRSN is a 62 mA, 125 V AC surface mount board fuse in the NANO²® 451 series. This fast-blow fuse is designed for board-level circuit protection in applications requiring compact, high-density mounting. The part is active in production with full RoHS3 compliance and CSA/UR approvals. Equivalent and substitute parts are identified to support procurement flexibility, inventory management, and design continuity across compatible NANO²® series fuses with identical electrical and mechanical specifications.

Substiute Parts

0451.062MRSN

Littelfuse Inc.In Stock: 7590451.062MRSN Datasheet

Current PartRFQ

0448.062MR

Littelfuse Inc.In Stock: 24520448.062MR Datasheet

Parametric EquivalentRFQ

0453.062MR

Littelfuse Inc.In Stock: 21280453.062MR Datasheet

Parametric EquivalentRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitute parts for the 0451.062MRSN are qualified based on the following critical parameters that determine functional interchangeability:

• Current Rating: 62 mA (exact match required)
• Voltage Rating (AC): 125 V (exact match required)
• Response Time: Fast Blow (exact match required)
• Mounting Type: Surface Mount (exact match required)
• Package / Case: 2-SMD, Square End Block (exact match required)
• Physical Dimensions: 0.240" L x 0.106" W x 0.106" H (exact match required)
• Operating Temperature Range: -55°C to 125°C (exact match required)
• RoHS3 Compliance: Required
• Moisture Sensitivity Level: 1 (Unlimited)

The substitute parts identified—Littelfuse 0448.062MR and 0453.062MR—meet all electrical and mechanical requirements for direct substitution. Both parts are from the NANO²® series, share identical current ratings, voltage ratings, response characteristics, and physical form factors. The primary distinction is DC voltage rating capability and series designation, which do not affect AC-only applications.

Parameter Comparison

Engineering Selection Recommendations

All three parts—0451.062MRSN, 0448.062MR, and 0453.062MR—are active production components with full RoHS3 compliance and regulatory approvals suitable for industrial and commercial applications. Selection between these parts should be based on:

• Regulatory certification requirements: The 0451.062MRSN carries CSA and UR approvals, while the 0448.062MR and 0453.062MR carry CSA and UL approvals. Verify that the required certification body is acceptable for your application.
• DC voltage capability: The 0448.062MR and 0453.062MR are rated for 125 V DC in addition to 125 V AC, providing broader application coverage for mixed-signal environments.
• Inventory availability: Current stock levels are 684 pcs (0451.062MRSN), 2400 pcs (0448.062MR), and 2087 pcs (0453.062MR).
• Melting I²t characteristics: The 0451.062MRSN and 0453.062MR share identical melting I²t values (0.00019), while the 0448.062MR has a slightly higher value (0.00023), which may affect thermal response in edge-case scenarios.

Frequently Asked Questions (FAQ)

Q: Can the 0448.062MR or 0453.062MR be used as direct replacements for the 0451.062MRSN in AC-only circuits?

A: Yes. Both substitute parts meet all electrical and mechanical specifications required for AC operation at 125 V, 62 mA. The additional DC voltage rating does not affect AC performance and does not create compatibility issues.

Q: What is the significance of the different approval agencies (UR vs. UL)?

A: UR (Underwriters' Laboratories of Canada) and UL (Underwriters Laboratories) are distinct certification bodies. Verify that your application or regional requirements accept the specific certification body listed for your selected part. Both are recognized safety standards organizations.

Q: Are the physical dimensions identical across all three parts?

A: Yes. All three parts share identical dimensions of 0.240" L x 0.106" W x 0.106" H (6.10mm x 2.69mm x 2.69mm) and the same 2-SMD, Square End Block package, ensuring mechanical interchangeability on PCB layouts.

Q: What does the difference in melting I²t values mean?

A: Melting I²t is a measure of the thermal energy required to melt the fuse element. The 0451.062MRSN and 0453.062MR have melting I²t of 0.00019, while the 0448.062MR has 0.00023. This slight difference may affect response time in high-current transient conditions, though all three are classified as fast-blow fuses.

Q: Are all three parts RoHS3 compliant?

A: Yes. All three parts carry ROHS3 Compliant status and are suitable for applications requiring RoHS compliance.

Q: What is the Moisture Sensitivity Level (MSL) significance?

A: All three parts have MSL 1 (Unlimited), indicating no moisture sensitivity restrictions. These parts can be stored and handled without special moisture control measures.