Littelfuse 0451.315NRL Surface Mount Board Mount Fuse Equivalent & Substitute Parts

Part Overview

The Littelfuse 0451.315NRL is a 315 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 status and widely used in industrial and consumer electronics requiring reliable overcurrent protection.

Equivalent and substitute parts are identified based on matching electrical ratings (current, voltage), mechanical compatibility (package type, dimensions), response characteristics (fast-blow), and regulatory approvals (UL, CSA certifications).

Substiute Parts

0451.315NRL

Littelfuse Inc.In Stock: 9070451.315NRL Datasheet

Current PartRFQ

0448.315MR

Littelfuse Inc.In Stock: 103970448.315MR Datasheet

Parametric EquivalentRFQ

0451.315MRL

Littelfuse Inc.In Stock: 72030451.315MRL Datasheet

Parametric EquivalentRFQ

0453.315MR

LittelfuseIn Stock: 73340453.315MR Datasheet

Parametric EquivalentRFQ

SF-2410FP0315T-2

Bourns Inc.In Stock: 3131SF-2410FP0315T-2 Datasheet

DirectRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the 0451.315NRL is determined by the following critical parameters:

• Current Rating: 315 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 @ Rated Voltage (exact match required)
• Operating Temperature: -55°C to 125°C (exact match required)
• Regulatory Approvals: UL and/or CSA certification (required)

All identified substitute parts meet these criteria. Variations in secondary parameters such as melting I²t, DC cold resistance, and manufacturer series do not prevent substitution when primary electrical and mechanical parameters are identical.

Parameter Comparison

Engineering Selection Recommendations

All identified substitute parts are active in production status and carry appropriate regulatory certifications (UL and/or CSA). Selection among equivalent parts should be based on:

1. Availability: Littelfuse 0448.315MR offers the highest inventory (10,300 pcs), followed by 0451.315MRL (7,100 pcs) and 0453.315MR (7,238 pcs). Bourns SF-2410FP0315T-2 has lower availability (3,033 pcs).

2. Manufacturer Preference: Littelfuse NANO²® series parts (0451.315NRL, 0451.315MRL, 0448.315MR, 0453.315MR) maintain consistent electrical characteristics within the same manufacturer ecosystem. Bourns SingleFuse™ SF-2410FP0315T-2 provides cross-manufacturer compatibility.

3. Secondary Parameter Considerations: DC cold resistance and melting I²t vary among substitutes. The 0451.315NRL, 0451.315MRL, and 0453.315MR share identical melting I²t (0.0311) and DC cold resistance (0.3918 Ohms), providing the closest electrical behavior match. The 0448.315MR exhibits higher DC cold resistance (0.79 Ohms) and lower melting I²t (0.0265). The Bourns part shows significantly higher melting I²t (0.1365) and DC cold resistance (0.843 Ohms).

4. Dimensional Tolerance: The Bourns SF-2410FP0315T-2 has slightly reduced height and width dimensions (2.59 mm vs. 2.69 mm), which may affect PCB layout compatibility in space-constrained applications.

Frequently Asked Questions (FAQ)

Q: Can I substitute the 0451.315NRL with the 0448.315MR?

A: Yes. Both parts share identical current rating (315 mA), voltage ratings (125 V AC/DC), response time (fast-blow), mounting type (surface mount), package configuration (2-SMD, Square End Block), breaking capacity (50 A), operating temperature range (-55°C to 125°C), and regulatory approvals (UL, CSA). The 0448.315MR is a parametric equivalent. Secondary differences in melting I²t and DC cold resistance do not prevent substitution when primary electrical and mechanical parameters match.

Q: What is the difference between the Littelfuse NANO²® series parts?

A: The 0451.315NRL (NANO²® 451), 0451.315MRL (NANO²® 451), 0448.315MR (NANO²® 448), and 0453.315MR (NANO²® 453) are all functionally equivalent for the specified 315 mA, 125 V AC/DC application. The series designation reflects internal design iterations within Littelfuse's product line. The 0451.315NRL and 0451.315MRL belong to the same NANO²® 451 series and share identical melting I²t (0.0311) and DC cold resistance (0.3918 Ohms). The 0448.315MR (NANO²® 448) exhibits different thermal characteristics (melting I²t 0.0265, DC cold resistance 0.79 Ohms). All parts meet the same regulatory and performance requirements.

Q: Can I use the Bourns SF-2410FP0315T-2 as a direct replacement?

A: Yes. The Bourns SF-2410FP0315T-2 meets all primary electrical and mechanical substitution criteria: 315 mA current rating, 125 V AC/DC voltage ratings, fast-blow response, surface mount configuration, 2-SMD Square End Block package, 50 A breaking capacity, and -55°C to 125°C operating temperature. It carries UL and cUL certifications. However, it exhibits higher melting I²t (0.1365 vs. 0.0311) and DC cold resistance (0.843 vs. 0.3918 Ohms), and has slightly reduced dimensions (2.59 mm vs. 2.69 mm height and width). Verify PCB layout compatibility before substitution.

Q: Are all these parts RoHS compliant?

A: Yes. All identified substitute parts are ROHS3 compliant and REACH unaffected, meeting environmental regulatory requirements for electronic component manufacturing and use.

Q: What does "2-SMD, Square End Block" package mean?

A: This designation indicates a surface mount device (SMD) fuse with two solder pads in a square-ended block configuration. The fuse element is housed in a compact rectangular body designed for automated PCB assembly. All identified parts use this identical package type, ensuring mechanical and electrical compatibility on the same PCB footprint.