Littelfuse 0451001.MRSN Surface Mount Board Mount Fuse Equivalent & Substitute Parts

Part Overview

The Littelfuse 0451001.MRSN is a 1 A, 125 V AC/DC surface mount board mount fuse in the NANO²® 451 series, packaged in 2-SMD Square End Block configuration. This component is designed for circuit protection in applications requiring fast-blow response characteristics. The part is currently active in production with full RoHS3 compliance and CSA, UR regulatory approvals. Equivalent and substitute parts are identified to support procurement flexibility, inventory optimization, and supply chain continuity.

Substiute Parts

0451001.MRSN

Littelfuse Inc.In Stock: 18100451001.MRSN Datasheet

Current PartRFQ

0448001.MR

Littelfuse Inc.In Stock: 202390448001.MR Datasheet

Parametric EquivalentRFQ

0451001.MRL

Littelfuse Inc.In Stock: 1802730451001.MRL Datasheet

Parametric EquivalentRFQ

0451001.NRL

LittelfuseIn Stock: 57640451001.NRL Datasheet

Parametric EquivalentRFQ

0453001.MR

Littelfuse Inc.In Stock: 211270453001.MR Datasheet

Parametric EquivalentRFQ

SF-2410FP100T-2

Bourns Inc.In Stock: 2299SF-2410FP100T-2 Datasheet

DirectRFQ

SF-2410HI100T-2

Bourns Inc.In Stock: 3688SF-2410HI100T-2 Datasheet

DirectRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitute parts for the 0451001.MRSN are classified based on strict electrical and mechanical parameter equivalence:

Parametric Equivalents (Littelfuse NANO²® Series): Parts 0448001.MR, 0451001.MRL, 0451001.NRL, and 0453001.MR share identical electrical specifications (1 A, 125 V AC/DC, Fast Blow, 50 A breaking capacity) and mechanical form factor (2-SMD Square End Block, 0.240" L × 0.106" W × 0.106" H). These parts differ only in packaging format (Tape & Reel vs. Cut Tape & Digi-Reel®) and minor variations in DC cold resistance and melting I²t values within acceptable tolerance ranges.

Direct Equivalents (Bourns SinglFuse™ Series): Parts SF-2410FP100T-2 and SF-2410HI100T-2 meet all critical electrical parameters (1 A, 125 V AC/DC, Fast Blow, 50 A breaking capacity) and mechanical specifications (2-SMD Square End Block, Surface Mount). These parts represent cross-manufacturer alternatives with slightly different physical dimensions (0.240" L × 0.102" W × 0.102" H) and melting I²t characteristics.

Key Parameters Determining Substitutability:

• Current Rating: 1 A (exact match required)
• Voltage Rating: 125 V AC and 125 V DC (exact match required)
• Response Time: Fast Blow (exact match required)
• Package / Case: 2-SMD, Square End Block (exact match required)
• Mounting Type: Surface Mount (exact match required)
• Breaking Capacity: 50 A (exact match required)

Parameter Comparison

Engineering Selection Recommendations

Littelfuse NANO²® Series (0448001.MR, 0451001.MRL, 0451001.NRL, 0453001.MR): These parts maintain full electrical and mechanical equivalence to the 0451001.MRSN. Selection among these variants depends on packaging requirements and regulatory compliance scope. The 0451001.MRL offers the highest inventory availability (180,200 pcs) with CSA, PSE, and UL approvals. The 0451001.NRL provides Tape & Reel packaging identical to the main part with equivalent certifications. The 0448001.MR offers Cut Tape & Digi-Reel® packaging with PSE approval addition but exhibits lower DC cold resistance (0.0863 Ω vs. 0.153 Ω).

Bourns SinglFuse™ Series (SF-2410FP100T-2, SF-2410HI100T-2): These cross-manufacturer alternatives satisfy all critical electrical parameters and mechanical form factors. The SF-2410FP100T-2 provides melting I²t of 0.4143 with cUL and UL certifications. The SF-2410HI100T-2 exhibits significantly higher melting I²t (1.9933) with REACH Affected status, suitable for applications requiring extended thermal response characteristics. Both Bourns parts feature slightly reduced physical dimensions (0.102" W × 0.102" H vs. 0.106" W × 0.106" H).

Regulatory Compliance: All substitute parts maintain RoHS3 compliance and MSL 1 (Unlimited) moisture sensitivity rating. The main part carries CSA and UR approvals; substitute parts expand certification coverage to include UL, PSE, and cUL where applicable. Selection should align with target market regulatory requirements.

Frequently Asked Questions (FAQ)

Q: Can 0451001.NRL be used as a direct replacement for 0451001.MRSN?

A: Yes. Both parts are from the NANO²® 451 series with identical electrical specifications (1 A, 125 V AC/DC, Fast Blow), mechanical form factor (2-SMD Square End Block), and physical dimensions (0.240" L × 0.106" W × 0.106" H). The primary difference is packaging format: 0451001.MRSN uses Tape & Reel (TR), while 0451001.NRL also uses Tape & Reel (TR). Both are functionally equivalent for circuit protection applications.

Q: What is the difference between Littelfuse and Bourns fuse options?

A: Littelfuse NANO²® parts (0448001.MR, 0451001.MRL, 0451001.NRL, 0453001.MR) and Bourns SinglFuse™ parts (SF-2410FP100T-2, SF-2410HI100T-2) meet identical electrical specifications and breaking capacity. Differences exist in melting I²t characteristics, DC cold resistance, physical dimensions (Bourns parts are slightly smaller: 0.102" vs. 0.106" width/height), and regulatory certifications. Bourns parts carry cUL and UL approvals; Littelfuse parts offer broader certification coverage including PSE and CSA.

Q: Does packaging format affect electrical performance?

A: No. Packaging format (Tape & Reel vs. Cut Tape & Digi-Reel®) affects only supply chain logistics and automated assembly compatibility. Electrical and thermal characteristics remain unchanged. Selection should be based on manufacturing equipment requirements and procurement volume.

Q: Are there any temperature or environmental differences between substitute parts?

A: All substitute parts share identical operating temperature range (-55°C to 125°C) and MSL 1 (Unlimited) moisture sensitivity rating. Environmental performance is equivalent across all listed alternatives.

Q: What is the significance of melting I²t variation?

A: Melting I²t represents thermal energy required to melt the fuse element. The 0451001.MRSN specifies 0.459 A²s. Littelfuse NANO²® 451 and 453 series maintain this value (0.459 A²s). The Bourns SF-2410FP100T-2 provides 0.4143 A²s (slightly lower), while SF-2410HI100T-2 provides 1.9933 A²s (significantly higher). These variations affect response time characteristics under transient overcurrent conditions. Selection should align with application-specific thermal response requirements.

Q: Which substitute part offers the best inventory availability?

A: The 0451001.MRL (Littelfuse NANO²® 451, Cut Tape & Digi-Reel® packaging) provides the highest inventory availability at 180,200 pcs. The 0451001.MRSN main part has 1,766 pcs available. For immediate procurement, 0451001.MRL or 0453001.MR (21,088 pcs) are recommended alternatives.