Littelfuse 0451020.MRSN Surface Mount Fuse - Equivalent & Substitute Parts

Part Overview

The Littelfuse 0451020.MRSN is a 20A, 65V AC/DC surface mount board fuse in the NANO²® 451 series. This fast-blow fuse is designed for circuit protection in compact electronic applications requiring SMD mounting. The part is currently active in production with full cURus approval certification. Substitute parts are identified to address packaging availability, inventory requirements, or specific supply chain preferences while maintaining identical electrical and mechanical performance.

Substiute Parts

0451020.MRSN

LittelfuseIn Stock: 312860451020.MRSN Datasheet

Current PartRFQ

0451020.MRL

Littelfuse Inc.In Stock: 14860451020.MRL Datasheet

Parametric EquivalentRFQ

Key Parameters

Substitute Part Grouping Explanation

The 0451020.MRL is a parametric equivalent to the 0451020.MRSN. Substitution is valid based on the following criteria:

Electrical Parameters (Identical):

• Current Rating: 20 A
• Voltage Rating: 65 V AC / 65 V DC
• Response Time: Fast Blow
• Breaking Capacity: 100 A AC / 150 A DC
• Melting I²t: 154
• DC Cold Resistance: 0.00244 Ohms

Mechanical Parameters (Identical):

• Mounting Type: Surface Mount
• Package / Case: 2-SMD, Square End Block
• Physical Dimensions: 0.240" L × 0.106" W × 0.106" H (6.10mm × 2.69mm × 2.69mm)

Thermal Parameters (Identical):

• Operating Temperature Range: -55°C to 125°C

Regulatory & Compliance (Identical):

• Series: NANO²® 451
• Approval Agency: cURus
• RoHS Status: ROHS3 Compliant
• ECCN: EAR99
• HTSUS: 8536.10.0040

The only difference between these parts is packaging format: the main part (0451020.MRSN) is supplied in Tape & Reel (TR) format, while the substitute (0451020.MRL) is supplied in Cut Tape (CT) & Digi-Reel® format.

Parameter Comparison

Engineering Selection Recommendations

Both the 0451020.MRSN and 0451020.MRL are active production parts with identical electrical, mechanical, and thermal specifications. Selection between these parts should be based on packaging and supply chain requirements:

0451020.MRSN (Tape & Reel): Select this part for high-volume automated assembly operations requiring continuous reel feeding. Tape & Reel packaging is optimized for pick-and-place equipment and provides efficient component handling in production environments.

0451020.MRL (Cut Tape & Digi-Reel®): Select this part for lower-volume applications, prototype builds, or situations where smaller quantity increments are required. Cut Tape & Digi-Reel® packaging provides flexibility for manual or semi-automated assembly processes.

Both parts carry cURus approval certification, ROHS3 compliance, and EAR99 export classification. No electrical or mechanical redesign is required when substituting between these part numbers. The choice is purely a packaging and logistics decision.

Frequently Asked Questions (FAQ)

Q: Can I substitute 0451020.MRL for 0451020.MRSN in my circuit design?

A: Yes. Both parts are electrically and mechanically identical. The 20A current rating, 65V AC/DC voltage rating, fast-blow response, breaking capacity, and all thermal specifications are identical. Substitution is valid for any application using the main part number.

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 automated pick-and-place assembly. Cut Tape (CT) & Digi-Reel® packaging provides components in smaller, pre-cut quantities on a reel, offering flexibility for lower-volume or manual assembly processes. Both formats contain the same component.

Q: Are there any compliance or certification differences between these parts?

A: No. Both parts carry identical cURus approval, ROHS3 compliance, EAR99 export classification, and HTSUS coding. Regulatory and compliance status is identical.

Q: Can I use these parts interchangeably on the same PCB assembly?

A: Yes. The physical dimensions (0.240" L × 0.106" W × 0.106" H), SMD footprint (2-SMD, Square End Block), and all electrical parameters are identical. PCB layout and assembly processes require no modification.

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

A: The melting I²t value of 154 defines the thermal energy required to melt the fuse element. This parameter determines the fuse's response to overcurrent conditions. Both parts have identical I²t values, ensuring identical protection characteristics.

Q: Are there inventory considerations when choosing between these parts?

A: Yes. The 0451020.MRSN (Tape & Reel) has 31,200 pieces in stock, while the 0451020.MRL (Cut Tape & Digi-Reel®) has 1,420 pieces in stock. Availability may influence selection based on project timeline and volume requirements.