Littelfuse 045204.6NRL Surface Mount Board Mount Fuse Equivalent & Substitute Parts

Part Overview

The Littelfuse 045204.6NRL is a 4.6 A, 125 V AC/DC surface mount board mount fuse in the NANO²® 452 series. This fuse is designed for circuit protection in applications requiring slow blow response characteristics with a 2-SMD square end block package. The part is currently active in production with full inventory availability. Equivalent and substitute parts are identified to support procurement flexibility, design revisions, and supply chain continuity.

Substiute Parts

045203.5NRL

Littelfuse Inc.In Stock: 2868045203.5NRL Datasheet

Current PartRFQ

044903.5MR

Littelfuse Inc.In Stock: 1947044903.5MR Datasheet

Parametric EquivalentRFQ

045203.5MRL

Littelfuse Inc.In Stock: 18158045203.5MRL Datasheet

Parametric EquivalentRFQ

045403.5MR

Littelfuse Inc.In Stock: 16346045403.5MR Datasheet

Parametric EquivalentRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the 045204.6NRL is determined by strict equivalence across the following critical parameters:

• Current Rating: 4.6 A (exact match required)
• Voltage Rating: 125 V AC and 125 V DC (exact match required)
• Response Time: Slow 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 to 125°C (exact match required)

All identified substitute parts meet these criteria. Variations in series designation (NANO²® 452, 449, 454), DC cold resistance, melting I²t values, and approval agency certifications do not affect functional interchangeability within the specified electrical and mechanical parameters.

Parameter Comparison

Engineering Selection Recommendations

All substitute parts listed are functionally equivalent to the 045204.6NRL based on electrical and mechanical parameters. Selection among these parts should be based on the following factors:

Approval Agency Compliance: The 045204.6NRL carries CSA, PSE, and UR certifications. The 045204.6MRL and 045404.6MR maintain equivalent certification coverage (CSA, PSE, UR/UL). The 044904.6MR carries cURus and PSE certifications, which may require evaluation against specific application requirements.

Inventory Availability: The 045204.6MRL offers the highest inventory level (18,148 pcs), followed by 045404.6MR (16,269 pcs), 045204.6NRL (2,839 pcs), and 044904.6MR (1,915 pcs).

Series Designation: The 045204.6NRL and 045204.6MRL are both NANO²® 452 series parts with identical DC cold resistance (0.0224 Ohms) and melting I²t (26.53). The 045404.6MR is NANO²® 454 series with the same electrical characteristics. The 044904.6MR is NANO²® 449 series with slightly higher melting I²t (32.7) and DC cold resistance (0.0261 Ohms).

All parts are active products with ROHS3 compliance and unlimited moisture sensitivity rating.

Frequently Asked Questions (FAQ)

Q: Can the 044904.6MR be used as a direct replacement for the 045204.6NRL?

A: The 044904.6MR meets all critical electrical and mechanical substitution criteria: 4.6 A current rating, 125 V AC/DC voltage rating, slow blow response, surface mount configuration, and identical physical dimensions. The higher melting I²t (32.7 vs. 26.53) and DC cold resistance (0.0261 vs. 0.0224 Ohms) do not affect functional interchangeability within the specified parameters. Approval agency differences (cURus, PSE vs. CSA, PSE, UR) should be evaluated against application-specific compliance requirements.

Q: What is the difference between the NANO²® 452, 449, and 454 series?

A: Series designation reflects internal design variations within the NANO²® product family. All identified parts maintain identical current rating, voltage rating, response time, mounting type, package configuration, and physical dimensions. Differences in melting I²t and DC cold resistance are secondary characteristics that do not affect substitution eligibility based on the specified parameters.

Q: Are all substitute parts available in the same packaging format?

A: All substitute parts are supplied in Tape & Reel (TR) packaging, consistent with the 045204.6NRL.

Q: Which substitute part should be selected for new designs?

A: Selection should prioritize parts with the highest inventory availability and certification coverage matching application requirements. The 045204.6MRL (NANO²® 452 series) offers the highest inventory level and maintains identical electrical characteristics and approval agencies as the 045204.6NRL.

Q: Can these fuses be used interchangeably on the same PCB assembly?

A: All substitute parts share identical physical dimensions (0.240" L x 0.106" W x 0.106" H), 2-SMD square end block package configuration, and surface mount mounting type. PCB footprints and assembly processes require no modification for substitution.