Littelfuse 045101.5NR Surface Mount Board Mount Fuse Equivalent & Substitute Parts

Part Overview

The Littelfuse 045101.5NR is a 1.5 A, 125 V AC/DC surface mount board mount fuse in the NANO²® 451 series, packaged as a 2-SMD square end block component. This part is classified as obsolete, making equivalent and substitute parts necessary for ongoing design support and production continuity. The fuse provides fast-blow protection with a 50 A breaking capacity and operates across the -55°C to 125°C temperature range. Substitute parts maintain identical electrical and mechanical specifications while offering active product status and improved compliance profiles.

Substiute Parts

045101.5NR

Littelfuse Inc.In Stock: 891045101.5NR Datasheet

Current PartRFQ

045101.5NRL

Littelfuse Inc.In Stock: 8980045101.5NRL Datasheet

DirectRFQ

044801.5MR

Littelfuse Inc.In Stock: 15338044801.5MR Datasheet

Parametric EquivalentRFQ

045101.5MRL

Littelfuse Inc.In Stock: 20133045101.5MRL Datasheet

Parametric EquivalentRFQ

045301.5MR

Littelfuse Inc.In Stock: 3392045301.5MR Datasheet

Parametric EquivalentRFQ

045301.5NR

Littelfuse Inc.In Stock: 5438045301.5NR Datasheet

Parametric EquivalentRFQ

SF-2410FP150T-2

Bourns Inc.In Stock: 11330SF-2410FP150T-2 Datasheet

DirectRFQ

SF-2410HI150T-2

Bourns Inc.In Stock: 1141SF-2410HI150T-2 Datasheet

DirectRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution for the 045101.5NR is determined by strict equivalence across the following critical parameters:

• Current Rating: 1.5 A (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: -55°C to 125°C (exact match required)

Substitute parts are grouped into two categories:

Littelfuse Direct Substitutes (Same Manufacturer, Same Series or Related Series): Parts 045101.5NRL, 045101.5MRL, 044801.5MR, 045301.5MR, and 045301.5NR maintain identical electrical and mechanical parameters. These parts differ primarily in packaging format (Tape & Reel vs. Cut Tape & Digi-Reel®) and product status (Active vs. Obsolete), with minor variations in melting I²t and DC cold resistance within acceptable engineering tolerances.

Cross-Manufacturer Substitutes (Bourns Inc.): Parts SF-2410FP150T-2 and SF-2410HI150T-2 from Bourns Inc. meet all critical electrical and mechanical parameters. These parts are functionally equivalent but exhibit differences in melting I²t values (1.0606 and 2.82 respectively, compared to 0.853 for the Littelfuse part) and DC cold resistance, reflecting different thermal response characteristics within the fast-blow classification.

Parameter Comparison

Engineering Selection Recommendations

For Direct Replacement with Active Product Status: Select 045101.5NRL, 045101.5MRL, 045301.5MR, or 045301.5NR. These Littelfuse parts maintain identical electrical characteristics to the obsolete 045101.5NR while offering active product status and ROHS3 compliance. The choice between these parts depends on packaging requirements: Tape & Reel format for automated assembly (045101.5NRL, 045301.5MR, 045301.5NR) or Cut Tape & Digi-Reel® for mixed-volume production (045101.5MRL).

For Alternative Series Within Littelfuse Portfolio: Part 044801.5MR from the NANO²® 448 series provides active status and ROHS3 compliance with a slightly elevated melting I²t value of 0.9 (compared to 0.853). This part is suitable for applications where the thermal response characteristic difference is acceptable and inventory availability is a priority.

For Cross-Manufacturer Substitution: Bourns Inc. SinglFuse™ parts SF-2410FP150T-2 and SF-2410HI150T-2 are electrically and mechanically equivalent. SF-2410FP150T-2 exhibits a melting I²t of 1.0606, positioning it between standard Littelfuse parts and the higher-response SF-2410HI150T-2 (melting I²t of 2.82). Selection depends on thermal response requirements and supplier qualification status. Both parts carry ROHS3 compliance and active product status.

Compliance Considerations: All substitute parts except the original 045101.5NR are ROHS3 compliant. The SF-2410HI150T-2 carries REACH Affected status, requiring verification against specific application requirements. All parts maintain CSA, PSE, and UL certifications (Bourns parts carry cUL and UL certifications).

Frequently Asked Questions (FAQ)

Q: Can I use 045101.5NRL as a direct replacement for the obsolete 045101.5NR?

A: Yes. The 045101.5NRL is electrically and mechanically identical to the 045101.5NR, with the primary differences being active product status, ROHS3 compliance, and Tape & Reel packaging. No circuit modifications are required.

Q: What is the difference between the Littelfuse NANO²® 451 and NANO²® 448 series fuses?

A: Both series meet the same electrical and mechanical specifications for the 1.5 A, 125 V application. The 044801.5MR (NANO²® 448) exhibits a melting I²t of 0.9 compared to 0.853 for the 451 series, indicating a slightly slower thermal response. This difference is within the fast-blow classification and acceptable for most applications.

Q: How do Bourns SinglFuse™ parts compare to Littelfuse NANO²® fuses?

A: Bourns SF-2410FP150T-2 and SF-2410HI150T-2 are functionally equivalent in current, voltage, and breaking capacity. The primary differences are melting I²t values (1.0606 and 2.82 respectively) and DC cold resistance (0.114 and 0.057 Ω). These differences reflect distinct thermal response profiles within the fast-blow category. Selection should be based on application thermal requirements and supplier qualification.

Q: What packaging options are available for substitute parts?

A: Littelfuse substitutes are available in Tape & Reel (045101.5NRL, 045301.5MR, 045301.5NR) and Cut Tape & Digi-Reel® (045101.5MRL, 044801.5MR) formats. Bourns parts are supplied in Tape & Reel format. Choose based on assembly equipment compatibility and production volume requirements.

Q: Are there any compliance differences I should consider?

A: All substitute parts are ROHS3 compliant, whereas the original 045101.5NR is RoHS non-compliant. The SF-2410HI150T-2 carries REACH Affected status, requiring verification against specific regulatory requirements for your application region and end-use category.

Q: Can I mix different substitute parts in the same production run?

A: All listed substitutes meet identical electrical and mechanical specifications and are mechanically interchangeable on the PCB. However, mixing parts with different melting I²t values (particularly Bourns SF-2410HI150T-2 with its significantly higher value of 2.82) may affect circuit thermal response characteristics. Verify thermal performance through circuit simulation or testing if mixing parts with different I²t values.