Littelfuse 0451.080MRSN Surface Mount Fuse - Equivalent & Substitute Parts

Part Overview

The Littelfuse 0451.080MRSN is an 80 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-reliability protection. The part is actively manufactured and maintained in production status. Substitute parts may be required due to inventory availability, regional sourcing constraints, or specific application requirements for dual voltage (AC/DC) rated alternatives.

Substiute Parts

0451.080MRSN

Littelfuse Inc.In Stock: 9770451.080MRSN Datasheet

Current PartRFQ

0451.080MRL

Littelfuse Inc.In Stock: 28730451.080MRL Datasheet

Parametric EquivalentRFQ

Key Parameters

Substitute Part Grouping Explanation

The Littelfuse 0451.080MRL qualifies as a parametric equivalent to the 0451.080MRSN based on the following substitution criteria:

Matching Parameters (Substitution Basis):

• Current Rating: 80 mA (identical)
• Voltage Rating - AC: 125 V (identical)
• Response Time: Fast Blow (identical)
• Mounting Type: Surface Mount (identical)
• Package / Case: 2-SMD, Square End Block (identical)
• Physical Dimensions: 0.240" L x 0.106" W x 0.106" H (identical)
• Breaking Capacity @ Rated Voltage: 50A (identical)
• Melting I²t: 0.00033 (identical)
• DC Cold Resistance: 4.05 Ohms (identical)
• Operating Temperature Range: -55°C ~ 125°C (identical)
• Series: NANO²® 451 (identical)
• RoHS Status: ROHS3 Compliant (identical)
• MSL: 1 (Unlimited) (identical)

Distinguishing Feature: The 0451.080MRL includes an explicit DC voltage rating of 125 V, whereas the 0451.080MRSN specifies only AC voltage. Both parts maintain identical electrical and mechanical characteristics across all other parameters, making them functionally interchangeable in applications requiring 80 mA protection at 125 V AC.

Parameter Comparison

Engineering Selection Recommendations

Both the 0451.080MRSN and 0451.080MRL are active production parts from Littelfuse Inc. within the NANO²® 451 series. Selection between these parts should be based on the following criteria:

0451.080MRSN Selection: Use when AC-only voltage protection is required and inventory availability is sufficient. This part carries CSA and UR approvals.

0451.080MRL Selection: Use when dual AC/DC voltage protection is required or when AC-only specifications are not a constraint. This part carries CSA and UL approvals, providing broader regulatory coverage. The explicit DC voltage rating of 125 V makes this part suitable for applications with mixed AC/DC exposure.

Both parts maintain identical electrical performance characteristics, thermal operating range, and mechanical form factor. The choice between them is determined by application voltage requirements and regional certification preferences.

Frequently Asked Questions (FAQ)

Q: Can the 0451.080MRL be used as a direct replacement for the 0451.080MRSN?

A: Yes. Both parts are identical in current rating (80 mA), AC voltage rating (125 V), response time (Fast Blow), package type (2-SMD, Square End Block), and all electrical characteristics. The 0451.080MRL additionally specifies a 125 V DC rating, making it suitable for applications requiring dual voltage protection.

Q: What is the difference between these two part numbers?

A: The primary difference is the voltage rating specification. The 0451.080MRSN specifies 125 V AC only, while the 0451.080MRL specifies 125 V AC and 125 V DC. All other electrical and mechanical parameters are identical.

Q: Are the physical dimensions identical?

A: Yes. Both parts measure 0.240" L x 0.106" W x 0.106" H (6.10mm x 2.69mm x 2.69mm) and use the same 2-SMD, Square End Block package.

Q: Do these parts have the same approval certifications?

A: Both parts are CSA approved. The 0451.080MRSN carries UR approval, while the 0451.080MRL carries UL approval. Both certifications are recognized regulatory standards.

Q: What is the melting I²t value, and why is it important?

A: The melting I²t for both parts is 0.00033. This value indicates the thermal energy required to melt the fuse element and is critical for coordinating fuse protection with circuit design and upstream protective devices.

Q: Are both parts RoHS compliant?

A: Yes. Both the 0451.080MRSN and 0451.080MRL are ROHS3 compliant and have MSL rating of 1 (Unlimited), indicating no moisture sensitivity restrictions.