Littelfuse 0451.630NRL Surface Mount Fuse Equivalent & Substitute Parts

Part Overview

The Littelfuse 0451.630NRL is a 630 mA, 125 V AC/DC surface mount board fuse in the NANO²® 451 series. This fast-blow fuse is designed for circuit protection in applications requiring compact, high-density mounting on printed circuit boards. The part is actively manufactured and widely stocked, making it suitable for new designs and production applications. Equivalent substitute parts are available within the NANO²® fuse family, offering identical electrical performance with variations in internal construction and series designation.

Substiute Parts

0451.630NRL

Littelfuse Inc.In Stock: 9600451.630NRL Datasheet

Current PartRFQ

0448.630MR

Littelfuse Inc.In Stock: 30680448.630MR Datasheet

Parametric EquivalentRFQ

0451.630MRL

Littelfuse Inc.In Stock: 112530451.630MRL Datasheet

Parametric EquivalentRFQ

0453.630MR

LittelfuseIn Stock: 17970453.630MR Datasheet

Parametric EquivalentRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitute parts for the 0451.630NRL are qualified based on matching the following critical electrical and mechanical parameters:

• Current Rating: 630 mA
• Voltage Rating: 125 V AC / 125 V DC
• Response Time: Fast Blow
• Mounting Type: Surface Mount
• Package / Case: 2-SMD, Square End Block
• Physical Dimensions: 0.240" L x 0.106" W x 0.106" H
• Breaking Capacity: 50 A @ Rated Voltage
• Operating Temperature Range: -55°C to 125°C
• Approval Agencies: CSA, UL
• RoHS Compliance: ROHS3 Compliant

All substitute parts listed maintain identical electrical ratings and mechanical compatibility, ensuring direct substitution in circuit protection applications. Variations in internal construction (melting I²t and DC cold resistance) reflect different series designs within the NANO²® family but do not affect functional interchangeability for the specified electrical parameters.

Parameter Comparison

Engineering Selection Recommendations

All listed substitute parts maintain active product status and carry identical CSA and UL approvals, confirming their suitability for applications requiring regulatory compliance. The 0451.630NRL, 0451.630MRL, and 0453.630MR share identical melting I²t values (0.143) and DC cold resistance (0.305 Ohms), providing functionally equivalent thermal and electrical characteristics. The 0448.630MR variant exhibits a lower melting I²t (0.121) and reduced DC cold resistance (0.2821 Ohms), reflecting its NANO²® 448 series design but maintaining full electrical and mechanical compatibility for the specified 630 mA, 125 V rating.

Selection among these parts may be based on inventory availability, packaging preferences (all are supplied in Tape & Reel format), or supply chain considerations. All parts are ROHS3 compliant and carry MSL Level 1 (Unlimited) moisture sensitivity ratings, eliminating environmental handling restrictions.

Frequently Asked Questions (FAQ)

Q: Can the 0448.630MR be used as a direct replacement for the 0451.630NRL?

A: Yes. Both parts share identical electrical ratings (630 mA, 125 V AC/DC), response time (Fast Blow), mounting type (Surface Mount), package configuration (2-SMD, Square End Block), and physical dimensions. The difference in melting I²t and DC cold resistance reflects internal construction variations within the NANO²® family but does not affect functional interchangeability for the specified circuit protection application.

Q: What is the significance of the different NANO²® series designations (448, 451, 453)?

A: Series designations identify different internal construction designs within the NANO²® fuse family. All listed series maintain the same electrical performance specifications for the 630 mA, 125 V rating. Series differences do not impact substitution compatibility when electrical and mechanical parameters are identical.

Q: Are all substitute parts available in the same packaging format?

A: Yes. All substitute parts are supplied in Tape & Reel (TR) packaging, ensuring compatibility with automated assembly processes and consistent handling requirements.

Q: Do the substitute parts carry the same regulatory approvals?

A: Yes. All substitute parts carry CSA and UL approvals, maintaining compliance with the same regulatory standards as the 0451.630NRL.

Q: What is the difference between the 0451.630NRL and 0451.630MRL?

A: These parts are from the same NANO²® 451 series with identical electrical ratings, response time, and physical dimensions. The primary difference is packaging designation (NRL vs. MRL), which may reflect supplier or distribution channel variations. Both parts are functionally equivalent for circuit protection applications.

Q: Are there any temperature or environmental restrictions for these fuses?

A: All parts operate across the -55°C to 125°C temperature range and carry MSL Level 1 (Unlimited) moisture sensitivity ratings, eliminating special storage or handling requirements. ROHS3 compliance applies to all parts.