Littelfuse 045101.6MR Surface Mount Board Mount Fuse Equivalent & Substitute Parts

Part Overview

The Littelfuse 045101.6MR is a 1.6 A, 125 V AC/DC surface mount board mount fuse in the NANO²® 451 series with fast blow response characteristics. This part is classified as obsolete, making equivalent and substitute parts necessary for ongoing design support and procurement continuity. The part features a 2-SMD square end block package with a breaking capacity of 50 A at rated voltage and operates across a temperature range of -55°C to 125°C.

Substiute Parts

045101.6MR

Littelfuse Inc.In Stock: 909045101.6MR Datasheet

Current PartRFQ

045101.6MRL

Littelfuse Inc.In Stock: 65262045101.6MRL Datasheet

DirectRFQ

044801.6MR

Littelfuse Inc.In Stock: 1519044801.6MR Datasheet

Parametric EquivalentRFQ

045101.6NRL

Littelfuse Inc.In Stock: 1139045101.6NRL Datasheet

Parametric EquivalentRFQ

045301.6MR

Littelfuse Inc.In Stock: 1539045301.6MR Datasheet

Parametric EquivalentRFQ

045301.6NR

Littelfuse Inc.In Stock: 1123045301.6NR Datasheet

Parametric EquivalentRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the 045101.6MR is determined by strict equivalence across the following critical parameters:

• Current Rating: 1.6 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 at rated voltage (exact match required)
• Physical Dimensions: 0.240" L x 0.106" W x 0.106" H (exact match required)
• Approval Agencies: CSA, PSE, UL (all three required)

All substitute parts listed below meet these criteria. Variations in series designation (NANO²® 451, NANO²® 448, NANO²® 453), RoHS compliance status, and packaging format (bulk vs. tape & reel) do not affect functional equivalence for circuit protection applications.

Parameter Comparison

Engineering Selection Recommendations

For applications currently using the obsolete 045101.6MR, the following selection criteria apply:

Direct Replacement (Identical Electrical and Physical Characteristics):

• 045101.6MRL: Active product status with ROHS3 compliance. Identical electrical performance to the original part. Available in tape & reel packaging for automated assembly.
• 045101.6NRL: Active product status with ROHS3 compliance. Identical electrical performance to the original part. Available in tape & reel packaging.

Parametric Equivalent (Functionally Equivalent with Minor Variations):

• 044801.6MR: Active product status with ROHS3 compliance. Melting I²t of 1.122 versus 1.06 for the original part. DC cold resistance of 0.06261 Ω versus 0.058 Ω. All other electrical and physical parameters are identical. Suitable for applications where minor thermal response variations are acceptable.
• 045301.6MR: Active product status with ROHS3 compliance. Identical electrical performance to the original part. Different series designation (NANO²® 453 vs. NANO²® 451) with no functional impact.
• 045301.6NR: Active product status with ROHS3 compliance. Identical electrical performance to the original part. Different series designation (NANO²® 453 vs. NANO²® 451) with no functional impact.

All substitute parts carry CSA, PSE, and UL approvals consistent with the original part specification.

Frequently Asked Questions (FAQ)

Q: Can I use 045101.6MRL as a direct replacement for 045101.6MR? A: Yes. The 045101.6MRL is electrically and physically identical to the 045101.6MR. The primary difference is product status (active vs. obsolete) and packaging format (tape & reel vs. bulk). Both parts are rated for 1.6 A at 125 V AC/DC with fast blow response and identical breaking capacity.

Q: What is the difference between the NANO²® 451, NANO²® 448, and NANO²® 453 series? A: Series designation indicates internal design generation. All three series meet the same electrical specifications for the 1.6 A, 125 V rating. The NANO²® 448 series (044801.6MR) exhibits a slightly higher melting I²t value (1.122 vs. 1.06) and marginally higher DC cold resistance (0.06261 Ω vs. 0.058 Ω), which may affect thermal response characteristics in specific circuit conditions. The NANO²® 451 and NANO²® 453 series parts are electrically identical.

Q: Does packaging format affect electrical performance? A: No. Tape & reel (TR) and bulk packaging formats contain identical fuse elements and electrical characteristics. Packaging format is determined by assembly process requirements and does not alter circuit protection performance.

Q: Are all substitute parts RoHS compliant? A: The original 045101.6MR is RoHS non-compliant. All active substitute parts (045101.6MRL, 044801.6MR, 045101.6NRL, 045301.6MR, 045301.6NR) are ROHS3 compliant, meeting current environmental regulations.

Q: Can I use 044801.6MR if the original design specified 045101.6MR? A: Yes, with consideration of thermal response characteristics. The 044801.6MR is functionally equivalent with identical current, voltage, and breaking capacity ratings. The melting I²t difference (1.122 vs. 1.06) represents approximately a 5.8% increase in thermal energy required for fuse operation. This variation is within acceptable tolerance for most circuit protection applications but should be evaluated in designs with critical thermal response requirements.

Q: What certifications do these fuses carry? A: All parts listed carry CSA, PSE, and UL approvals, meeting international safety standards for circuit protection devices.