Littelfuse 045201.5MR Surface Mount Board Mount Fuse Equivalent & Substitute Parts

Part Overview

The Littelfuse 045201.5MR is a 1.5 A, 125 V AC/DC surface mount board mount fuse in the NANO²® 452 series. This part is classified as obsolete, making identification of active equivalent and substitute parts essential for ongoing design support and procurement continuity. Substitute parts maintain identical electrical ratings and mechanical dimensions while offering improved availability and compliance status.

Key Parameters

Parameter	Specification
Current Rating	1.5 A
Voltage Rating (AC)	125 V
Voltage Rating (DC)	125 V
Response Time	Slow Blow
Mounting Type	Surface Mount
Fuse Type	Board Mount (Cartridge Style Excluded)
Package / Case	2-SMD, Square End Block
Size / Dimension	0.240" L x 0.106" W x 0.106" H (6.10mm x 2.69mm x 2.69mm)
Breaking Capacity @ Rated Voltage	50 A
Operating Temperature Range	-55°C ~ 125°C

Substitute Part Grouping Explanation

Substitute parts for the 045201.5MR are qualified based on the following critical parameters:

Current Rating: 1.5 A (exact match required)
Voltage Rating: 125 V AC / 125 V DC (exact match required)
Response Time: Slow Blow (exact match required)
Package / Case: 2-SMD, Square End Block (exact match required)
Physical Dimensions: 0.240" L x 0.106" W x 0.106" H (exact match required)
Breaking Capacity: 50 A (exact match required)
Operating Temperature: -55°C ~ 125°C (exact match required)

All substitute parts listed maintain these parameters. Differences in series designation (NANO²® 452, 449, 454), packaging format (bulk vs. Tape & Reel), and compliance status do not affect electrical or mechanical interchangeability.

Parameter Comparison

Part Number	Manufacturer	Series	Current Rating	Voltage (AC/DC)	Response Time	Package / Case	Dimensions	Breaking Capacity	Melting I²t	DC Cold Resistance	Product Status	Packaging Format	RoHS Status
045201.5MR	Littelfuse	NANO²® 452	1.5 A	125 V / 125 V	Slow Blow	2-SMD, Square End Block	0.240" x 0.106" x 0.106" (6.10mm x 2.69mm x 2.69mm)	50 A	3.65	0.093 Ω	Obsolete	Bulk	Non-compliant
045201.5MRL	Littelfuse Inc.	NANO²® 452	1.5 A	125 V / 125 V	Slow Blow	2-SMD, Square End Block	0.240" x 0.106" x 0.106" (6.10mm x 2.69mm x 2.69mm)	50 A	3.65	0.093 Ω	Active	Tape & Reel (TR)	ROHS3 Compliant
045201.5NRL	Littelfuse Inc.	NANO²® 452	1.5 A	125 V / 125 V	Slow Blow	2-SMD, Square End Block	0.240" x 0.106" x 0.106" (6.10mm x 2.69mm x 2.69mm)	50 A	3.65	0.093 Ω	Active	Tape & Reel (TR)	ROHS3 Compliant
045401.5MR	Littelfuse Inc.	NANO²® 454	1.5 A	125 V / 125 V	Slow Blow	2-SMD, Square End Block	0.240" x 0.106" x 0.106" (6.10mm x 2.69mm x 2.69mm)	50 A	3.65	0.093 Ω	Active	Cut Tape (CT) & Digi-Reel®	ROHS3 Compliant
045401.5NR	Littelfuse Inc.	NANO²® 454	1.5 A	125 V / 125 V	Slow Blow	2-SMD, Square End Block	0.240" x 0.106" x 0.106" (6.10mm x 2.69mm x 2.69mm)	50 A	3.65	0.093 Ω	Active	Tape & Reel (TR)	ROHS3 Compliant
044901.5MR	Littelfuse Inc.	NANO²® 449	1.5 A	125 V / 125 V	Slow Blow	2-SMD, Square End Block	0.240" x 0.106" x 0.106" (6.10mm x 2.69mm x 2.69mm)	50 A	4.7	0.1186 Ω	Active	Tape & Reel (TR)	ROHS3 Compliant

Engineering Selection Recommendations

All substitute parts are electrically and mechanically interchangeable with the 045201.5MR based on identical current, voltage, response time, package, and dimensional specifications.

Primary Recommendation: 045201.5MRL is the direct series equivalent (NANO²® 452) in active production status with ROHS3 compliance and Tape & Reel packaging suitable for automated assembly.

Alternative Selections:

045201.5NRL: Same series (NANO²® 452) with active status and ROHS3 compliance; Tape & Reel format
045401.5MR: NANO²® 454 series with active status and ROHS3 compliance; Cut Tape & Digi-Reel® packaging
045401.5NR: NANO²® 454 series with active status and ROHS3 compliance; Tape & Reel format
044901.5MR: NANO²® 449 series with active status and ROHS3 compliance; Tape & Reel format (note: Melting I²t = 4.7 vs. 3.65 for other substitutes)

All substitute parts carry CSA, PSE, and UL/UR certifications consistent with the original part's approval agencies.

Frequently Asked Questions (FAQ)

Q: Can 045201.5MRL be used as a direct replacement for 045201.5MR?

A: Yes. Both parts are identical in electrical ratings (1.5 A, 125 V AC/DC, Slow Blow), mechanical dimensions (0.240" x 0.106" x 0.106"), and package type (2-SMD, Square End Block). The primary difference is packaging format (Tape & Reel vs. bulk) and compliance status (ROHS3 Compliant vs. non-compliant).

Q: What is the difference between the NANO²® 452, 449, and 454 series?

A: All three series maintain identical electrical and mechanical specifications for the 1.5 A, 125 V rating. Series designation reflects internal design generation. The 044901.5MR (NANO²® 449) exhibits a higher Melting I²t value (4.7 vs. 3.65), indicating slightly different thermal response characteristics, though all remain classified as Slow Blow fuses.

Q: Does packaging format affect electrical performance?

A: No. Tape & Reel (TR), Cut Tape (CT) & Digi-Reel®, and bulk packaging formats do not alter electrical or thermal performance. Selection depends on assembly process requirements and procurement volume.

Q: Are all substitute parts RoHS compliant?

A: All substitute parts listed are ROHS3 compliant. The original 045201.5MR is RoHS non-compliant. Compliance status should be verified against specific application requirements.

Q: Can I mix packaging formats in the same assembly?

A: Yes, provided the fuse specifications (current, voltage, response time, dimensions) remain constant. Packaging format selection is determined by manufacturing process capability, not electrical interchangeability.

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