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

Part Overview

The Littelfuse 045204.6MR is a 4.6 A, 125 V AC/DC surface mount board mount fuse in the NANO²® 452 series. This part is classified as obsolete. Equivalent and substitute parts are available from Littelfuse's current product lines, offering improved compliance status and maintained electrical performance characteristics. Substitution is necessary to ensure long-term supply chain reliability and compliance with current regulatory requirements.

Substiute Parts

045203.5MR

Littelfuse Inc.In Stock: 3038045203.5MR Datasheet

Current PartRFQ

045203.5MRL

Littelfuse Inc.In Stock: 18158045203.5MRL Datasheet

DirectRFQ

044903.5MR

Littelfuse Inc.In Stock: 1947044903.5MR Datasheet

Parametric EquivalentRFQ

045203.5NRL

Littelfuse Inc.In Stock: 2868045203.5NRL Datasheet

Parametric EquivalentRFQ

045403.5MR

Littelfuse Inc.In Stock: 16346045403.5MR Datasheet

Parametric EquivalentRFQ

045403.5NR

Littelfuse Inc.In Stock: 757045403.5NR Datasheet

Parametric EquivalentRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the 045204.6MR is determined by 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 substitute parts listed maintain these critical electrical and mechanical parameters. Variations in series designation (NANO²® 449, 452, 454), RoHS compliance status, and approval agency certifications do not affect functional interchangeability within the specified parameter constraints.

Parameter Comparison

Engineering Selection Recommendations

Direct Replacement (Identical Electrical & Mechanical Performance):

045204.6MRL is the direct active equivalent to the obsolete 045204.6MR. Both parts share identical NANO²® 452 series designation, melting I²t value of 26.53, and DC cold resistance of 0.0224 Ohms. The primary difference is product status (Active vs. Obsolete) and RoHS3 compliance. This part is available in Tape & Reel packaging.

Parametric Equivalents (Functionally Interchangeable):

044904.6MR, 045204.6NRL, 045404.6MR, and 045404.6NR maintain all critical electrical parameters (4.6 A, 125 V AC/DC, Slow Blow response, 50 A breaking capacity, -55°C to 125°C operating range). These parts differ in series designation and minor thermal characteristics (melting I²t and DC cold resistance variations). All are Active status products with RoHS3 compliance and Tape & Reel packaging.

Approval Agency Considerations:

The original 045204.6MR carries CSA, PSE, and UR certifications. Substitute parts maintain equivalent certifications: 045204.6MRL, 045204.6NRL, 045404.6MR, and 045404.6NR carry CSA, PSE, and UL certifications. The 044904.6MR carries cURus and PSE certifications. Selection should align with specific regulatory requirements for the target application.

Frequently Asked Questions (FAQ)

Q: Can 045204.6MRL be used as a direct replacement for the obsolete 045204.6MR?

A: Yes. Both parts are electrically and mechanically identical, with matching current rating (4.6 A), voltage rating (125 V AC/DC), response time (Slow Blow), melting I²t (26.53), and DC cold resistance (0.0224 Ohms). The primary difference is packaging format (Tape & Reel vs. Bulk) and compliance status (RoHS3 Compliant vs. non-compliant).

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

A: Series designation indicates the internal design generation. All listed parts maintain identical electrical performance at the specified 4.6 A, 125 V rating. Series differences do not affect functional interchangeability within the parameter constraints of this application.

Q: Are there differences in thermal performance between substitute parts?

A: The 044904.6MR exhibits a higher melting I²t value (32.7 vs. 26.53) and slightly higher DC cold resistance (0.0261 Ω vs. 0.0224 Ω) compared to the original part and most substitutes. These variations remain within the functional equivalence range for the specified 4.6 A, 125 V application.

Q: What packaging formats are available?

A: The original 045204.6MR is supplied in Bulk packaging. All active substitute parts (045204.6MRL, 044904.6MR, 045204.6NRL, 045404.6MR, 045404.6NR) are available in Tape & Reel format, which is standard for surface mount production environments.

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

A: For new designs, 045204.6MRL is the recommended primary choice, as it maintains identical electrical and mechanical specifications to the original part while offering Active product status and RoHS3 compliance. Alternative selections should be based on specific approval agency requirements and supply chain availability.

Q: Are all substitute parts RoHS3 compliant?

A: Yes. All active substitute parts listed (045204.6MRL, 044904.6MR, 045204.6NRL, 045404.6MR, 045404.6NR) are RoHS3 compliant. The original 045204.6MR is RoHS non-compliant.