Littelfuse 0451.400NRL Surface Mount Board Mount Fuse Equivalent & Substitute Parts

Part Overview

The Littelfuse 0451.400NRL is a 400 mA, 125 V AC/DC surface mount board mount fuse in the NANO²® 451 series. This fast-blow fuse is designed for circuit protection in applications requiring compact SMD packaging with 2-SMD, Square End Block configuration. The part is active in production with full CSA and UL approval certifications. Equivalent and substitute parts are identified based on matching electrical ratings, mechanical dimensions, and performance characteristics to ensure direct board-level compatibility.

Substiute Parts

0451.400NRL

Littelfuse Inc.In Stock: 11830451.400NRL Datasheet

Current PartRFQ

0448.400MR

Littelfuse Inc.In Stock: 61620448.400MR Datasheet

Parametric EquivalentRFQ

0451.400MRL

Littelfuse Inc.In Stock: 770900451.400MRL Datasheet

Parametric EquivalentRFQ

0453.400MR

Littelfuse Inc.In Stock: 134280453.400MR Datasheet

Parametric EquivalentRFQ

SF-2410FP040T-2

Bourns Inc.In Stock: 871SF-2410FP040T-2 Datasheet

DirectRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitute parts for the 0451.400NRL are classified based on matching the following critical parameters:

• Current Rating: 400 mA (exact match required)
• Voltage Rating: 125 V AC and 125 V DC (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)
• Breaking Capacity: 50 A (exact match required)
• Operating Temperature Range: -55°C to 125°C (exact match required)
• Approval Agencies: CSA and/or UL certification (required for regulatory compliance)

All identified substitutes meet these electrical and mechanical parameters. Variations in DC Cold Resistance and Melting I²t values remain within acceptable engineering tolerances for this fuse category and do not affect functional interchangeability in circuit protection applications.

Parameter Comparison

Engineering Selection Recommendations

All substitute parts listed are active production components with current regulatory certifications (CSA, UL, or cUL). Selection among equivalent parts should be based on:

• Availability: 0451.400MRL offers the highest inventory (77,055 pcs), followed by 0453.400MR (13,350 pcs), 0448.400MR (6,144 pcs), and SF-2410FP040T-2 (846 pcs).
• Manufacturer preference: Littelfuse NANO²® series parts (0448.400MR, 0451.400MRL, 0453.400MR) maintain consistent electrical performance within the same product family. The Bourns SF-2410FP040T-2 provides cross-manufacturer compatibility with equivalent electrical ratings.
• Dimensional tolerance: SF-2410FP040T-2 has slightly reduced width and height dimensions (0.102" vs. 0.106"), which may require PCB footprint verification for tight layout applications.
• Resistance and thermal characteristics: DC Cold Resistance and Melting I²t values vary slightly among substitutes but remain within acceptable tolerances for 400 mA fast-blow fuse applications.

Frequently Asked Questions (FAQ)

Q: Can the 0451.400NRL be directly replaced with 0451.400MRL? A: Yes. The 0451.400MRL is a parametric equivalent within the same NANO²® 451 series, matching all critical electrical and mechanical specifications. The primary difference is packaging designation (NRL vs. MRL tape and reel configuration), which does not affect functional performance.

Q: What is the difference between Littelfuse NANO²® series substitutes (0448.400MR, 0451.400MRL, 0453.400MR)? A: All three parts share identical electrical ratings (400 mA, 125 V AC/DC, Fast Blow, 50 A breaking capacity) and mechanical dimensions. They differ by series designation (448, 451, 453) and have minor variations in DC Cold Resistance (0.4895 Ω, 0.4233 Ω, and 0.56 Ω respectively) and Melting I²t values (0.0416, 0.0484, and 0.0484 respectively). These variations do not affect interchangeability in standard circuit protection applications.

Q: Is the Bourns SF-2410FP040T-2 a suitable substitute? A: Yes, the SF-2410FP040T-2 meets all critical electrical parameters and holds equivalent UL and cUL certifications. The physical dimensions are slightly smaller (0.102" width and height vs. 0.106"), requiring PCB footprint compatibility verification. The Melting I²t value (0.2149) is higher than Littelfuse equivalents, which may affect response characteristics in specific circuit designs.

Q: Are all substitutes RoHS3 compliant? A: Yes. All listed substitute parts are ROHS3 compliant and REACH unaffected, meeting current environmental and regulatory requirements.

Q: What packaging options are available? A: All parts are supplied in Tape & Reel (TR) packaging, standard for surface mount production assembly.

Q: Do all substitutes have the same operating temperature range? A: Yes. All substitute parts operate across the -55°C to 125°C temperature range, matching the main part specification.