Littelfuse 045104.6MRSN Surface Mount Board Fuse Equivalent & Substitute Parts

Part Overview

The Littelfuse 045104.6MRSN is a 4.6 A, 125 V AC surface mount board fuse in the NANO²® 451 series. This fast-blow fuse is designed for board-level protection in electronic equipment and is supplied in Tape & Reel packaging. The part is active and widely stocked, with 855 units available in new original condition. Equivalent and substitute parts are identified based on matching electrical ratings, mechanical dimensions, and packaging compatibility to support procurement flexibility and supply chain continuity.

Substiute Parts

045103.5MRSN

Littelfuse Inc.In Stock: 899045103.5MRSN Datasheet

Current PartRFQ

044803.5MR

Littelfuse Inc.In Stock: 1541044803.5MR Datasheet

Parametric EquivalentRFQ

045103.5MRL

Littelfuse Inc.In Stock: 9642045103.5MRL Datasheet

Parametric EquivalentRFQ

045303.5MR

Littelfuse Inc.In Stock: 5495045303.5MR Datasheet

Parametric EquivalentRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitute parts for the 045104.6MRSN are qualified based on the following criteria:

• Current Rating: 4.6 A (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)
• Breaking Capacity: 50 A (exact match required)
• Operating Temperature Range: -55°C ~ 125°C (exact match required)
• RoHS Compliance: ROHS3 Compliant (exact match required)
• Product Status: Active (exact match required)

Substitute parts may differ in series designation, packaging format (Tape & Reel vs. Cut Tape & Digi-Reel®), DC voltage rating specification, melting I²t values, and approval agency certifications, provided all core electrical and mechanical parameters remain identical.

Parameter Comparison

Engineering Selection Recommendations

All substitute parts listed maintain identical electrical and mechanical specifications required for direct board-level replacement of the 045104.6MRSN. Selection among these equivalents should be based on:

• Packaging format availability: The main part (045104.6MRSN) and 044804.6MR are supplied in Tape & Reel format, while 045104.6MRL and 045304.6MR are supplied in Cut Tape & Digi-Reel® format. Choose based on assembly equipment compatibility and procurement requirements.

• Regulatory certification scope: The main part carries CSA, METI, and UR approvals. Substitute parts carry CSA with UL and/or PSE certifications. Verify that the certification set meets application requirements in target markets.

• DC voltage rating specification: The main part does not specify a DC voltage rating. Substitute parts explicitly rate 125 V DC, providing additional operational flexibility for dual AC/DC applications.

• Inventory availability: Stock levels vary significantly across the four parts, ranging from 855 to 9535 units. Consider lead time and supply chain continuity when selecting alternatives.

• Melting I²t characteristic: The 044804.6MR exhibits a melting I²t of 2.3, compared to 2.469 for the main part and other substitutes. This represents a minor thermal characteristic difference within the same fast-blow response class.

Frequently Asked Questions (FAQ)

Q: Can the 044804.6MR be used as a direct replacement for the 045104.6MRSN?

A: Yes. The 044804.6MR is electrically and mechanically equivalent, with identical current rating (4.6 A), AC voltage rating (125 V), response time (Fast Blow), package type (2-SMD, Square End Block), and physical dimensions. Both are supplied in Tape & Reel packaging. The primary difference is series designation (NANO²® 448 vs. NANO²® 451) and regulatory certifications (CSA/UL/PSE vs. CSA/METI/UR).

Q: What is the difference between Tape & Reel and Cut Tape & Digi-Reel® packaging?

A: Tape & Reel (TR) packaging supplies components on a continuous reel suitable for high-speed automated assembly equipment. Cut Tape (CT) & Digi-Reel® packaging provides components in cut tape format with optional Digi-Reel® reeling, offering flexibility for lower-volume production or mixed-component assembly. Both formats contain identical components; selection depends on assembly line equipment and production volume.

Q: Are the substitute parts RoHS compliant?

A: Yes. All parts listed, including the main part 045104.6MRSN and all substitutes (044804.6MR, 045104.6MRL, 045304.6MR), are ROHS3 compliant.

Q: Does the main part support DC voltage applications?

A: The 045104.6MRSN does not specify a DC voltage rating in its datasheet. However, all substitute parts explicitly rate 125 V DC, making them suitable for AC/DC dual-voltage applications. If DC operation is required, select from the substitute parts.

Q: What is the significance of the melting I²t value difference in the 044804.6MR?

A: The 044804.6MR has a melting I²t of 2.3 compared to 2.469 for the main part and other substitutes. Both values fall within the fast-blow response classification. The lower I²t indicates slightly faster thermal response. This difference is within normal manufacturing tolerance for the same current rating and response class.

Q: Which substitute part has the highest inventory availability?

A: The 045104.6MRL has the highest inventory with 9535 units in stock, followed by 045304.6MR with 5450 units. The main part 045104.6MRSN has 855 units, and 044804.6MR has 1480 units.

Q: Are all parts approved by the same regulatory agencies?

A: No. The main part carries CSA, METI, and UR approvals. The substitute parts carry CSA with UL and/or PSE certifications. Verify that the certification set of the selected part meets requirements for your target market and application.