Littelfuse 0451003.MRSN Surface Mount Board Mount Fuse Equivalent & Substitute Parts

Part Overview

The Littelfuse 0451003.MRSN is a 3A 125VAC surface mount board mount fuse in the NANO²® 451 series, packaged in Tape & Reel (TR) format with 2-SMD Square End Block configuration. This fuse is designed for fast-blow protection in electronic circuits requiring 125V AC operation. The part is currently active in production with full RoHS3 compliance and international approvals (CSA, METI, UR). Equivalent substitute parts are available to accommodate different packaging requirements, inventory availability, or supply chain considerations while maintaining identical electrical and mechanical performance characteristics.

Substiute Parts

0451003.MRSN

Littelfuse Inc.In Stock: 14720451003.MRSN Datasheet

Current PartRFQ

0448003.MR

Littelfuse Inc.In Stock: 171320448003.MR Datasheet

Parametric EquivalentRFQ

0451003.MRL

Littelfuse Inc.In Stock: 302130451003.MRL Datasheet

Parametric EquivalentRFQ

0451003.NRL

Littelfuse Inc.In Stock: 103060451003.NRL Datasheet

Parametric EquivalentRFQ

0453003.MR

Littelfuse Inc.In Stock: 566290453003.MR Datasheet

Parametric EquivalentRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitute parts for the 0451003.MRSN are qualified based on strict equivalence across the following critical parameters:

Electrical Equivalence Criteria:

• Current Rating: 3 A (exact match required)
• Voltage Rating (AC): 125 V (exact match required)
• Response Time: Fast Blow (exact match required)
• Breaking Capacity @ Rated Voltage: 50 A (exact match required)
• Melting I²t: 1.65 (exact match required)
• DC Cold Resistance: 0.0227 Ohms (exact match required)

Mechanical Equivalence Criteria:

• Mounting Type: Surface Mount (exact match required)
• Package / Case: 2-SMD, Square End Block (exact match required)
• Size / Dimension: 0.240" L x 0.106" W x 0.106" H (exact match required)

Environmental & Compliance Criteria:

• Operating Temperature Range: -55°C ~ 125°C (exact match required)
• RoHS Status: ROHS3 Compliant (exact match required)
• Moisture Sensitivity Level: 1 (Unlimited) (exact match required)

The following Littelfuse parts meet all substitution criteria for the 0451003.MRSN:

• 0451003.MRL (Cut Tape & Digi-Reel® packaging)
• 0451003.NRL (Tape & Reel packaging)
• 0453003.MR (Tape & Reel packaging)

The part 0448003.MR qualifies as an electrical and mechanical equivalent with the exception of DC voltage rating (125V DC vs. AC-only specification on main part) and melting I²t variance (1.72 vs. 1.65), making it suitable for applications requiring dual AC/DC voltage operation.

Parameter Comparison

Engineering Selection Recommendations

All substitute parts listed maintain active product status with full RoHS3 compliance and international regulatory approvals. Selection between equivalent parts should be based on packaging and supply availability requirements:

0451003.MRL and 0451003.NRL are direct electrical and mechanical equivalents within the NANO²® 451 series. The 0451003.MRL offers Cut Tape & Digi-Reel® packaging with higher inventory availability (30,200 pcs), while 0451003.NRL maintains Tape & Reel packaging (10,263 pcs in stock).

0453003.MR is a full electrical and mechanical equivalent from the NANO²® 453 series with the highest inventory availability (56,556 pcs) and Tape & Reel packaging, providing optimal supply chain flexibility.

0448003.MR from the NANO²® 448 series qualifies as an electrical and mechanical equivalent with dual AC/DC voltage rating (125V AC / 125V DC) and marginally higher melting I²t (1.72 vs. 1.65). This part is suitable for applications requiring DC voltage protection capability and offers substantial inventory availability (17,025 pcs) in Cut Tape & Digi-Reel® packaging.

All parts carry identical approval agencies (CSA, UL, PSE) with the exception of the main part (CSA, METI, UR), maintaining compliance across international markets.

Frequently Asked Questions (FAQ)

Q: Can 0451003.MRL be used as a direct replacement for 0451003.MRSN?

A: Yes. Both parts are electrically and mechanically identical with 3A 125VAC fast-blow response, 50A breaking capacity, 1.65 melting I²t, and identical physical dimensions (0.240" L x 0.106" W x 0.106" H). The difference is packaging format: 0451003.MRSN uses Tape & Reel (TR), while 0451003.MRL uses Cut Tape (CT) & Digi-Reel®. Both are ROHS3 compliant with MSL 1 (Unlimited).

Q: What is the difference between 0451003.NRL and 0451003.MRL?

A: Both parts are electrically identical 3A 125VAC fuses with matching electrical parameters (1.65 melting I²t, 0.0227 Ohms DC cold resistance). The primary difference is packaging: 0451003.NRL uses Tape & Reel (TR) format with 10,263 pcs inventory, while 0451003.MRL uses Cut Tape (CT) & Digi-Reel® format with 30,200 pcs inventory. Selection depends on assembly equipment compatibility and supply requirements.

Q: Is 0448003.MR suitable for AC-only applications?

A: Yes. The 0448003.MR is rated for 125V AC operation and meets all electrical requirements for AC-only circuits. However, it includes additional 125V DC rating capability. The melting I²t is 1.72 compared to 1.65 for the main part, representing a 4.2% variance. DC cold resistance is 0.02445 Ohms versus 0.0227 Ohms for the main part.

Q: Can 0453003.MR replace 0451003.MRSN in production?

A: Yes. The 0453003.MR is a full electrical and mechanical equivalent with identical 3A 125VAC/DC fast-blow characteristics, 50A breaking capacity, 1.65 melting I²t, and 0.0227 Ohms DC cold resistance. Physical dimensions and operating temperature range (-55°C ~ 125°C) are identical. Both use 2-SMD Square End Block packaging. The 0453003.MR is from the NANO²® 453 series with highest inventory availability (56,556 pcs).

Q: What packaging formats are available for these equivalent parts?

A: Three packaging options are available: Tape & Reel (TR) format for 0451003.MRSN and 0451003.NRL and 0453003.MR; Cut Tape (CT) & Digi-Reel® format for 0451003.MRL and 0448003.MR. Selection depends on assembly line equipment specifications and minimum order quantity requirements.

Q: Are all substitute parts RoHS3 compliant?

A: Yes. All listed substitute parts (0448003.MR, 0451003.MRL, 0451003.NRL, 0453003.MR) are ROHS3 compliant with MSL 1 (Unlimited) moisture sensitivity rating, matching the main part 0451003.MRSN specifications.