Littelfuse 0451007.NR Surface Mount Board Mount Fuse Equivalent & Substitute Parts

Part Overview

The Littelfuse 0451007.NR is a 7 A, 125 V AC/DC surface mount board mount fuse in the NANO²® 451 series, packaged as 2-SMD with square end block configuration. This part is classified as obsolete. Equivalent and substitute parts are available from Littelfuse in active product status with improved compliance profiles, as well as direct alternatives from Bourns Inc. that maintain identical electrical and mechanical specifications.

Key Parameters

Parameter	Value
Current Rating	7 A
Voltage Rating (AC)	125 V
Voltage Rating (DC)	125 V
Response Time	Fast 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)
Operating Temperature Range	-55°C ~ 125°C
Breaking Capacity @ Rated Voltage	50A
Approval Agencies	CSA, PSE, UL

Substitute Part Grouping Explanation

Substitution for the 0451007.NR is determined by strict equivalence across the following parameters: current rating (7 A), AC voltage rating (125 V), DC voltage rating (125 V), response time (Fast Blow), mounting type (Surface Mount), fuse type (Board Mount), package configuration (2-SMD, Square End Block), physical dimensions (0.240" L x 0.106" W x 0.106" H), and operating temperature range (-55°C ~ 125°C).

Littelfuse substitutes within the NANO²® series (0451007.MRL, 0451007.NRL, 0453007.MR, 0453007.NR, 0448007.MR) maintain all core electrical and mechanical parameters. The 0476007.MR and 0476007.MRSN variants differ in breaking capacity (100A AC, 300A DC versus 50A) and melting I²t characteristics but preserve all other critical specifications.

Bourns Inc. SinglFuse™ series parts (SF-2410FP700T-2, SF-2410HI700T-2) provide direct functional equivalence with identical current, voltage, and package specifications. Minor dimensional variations exist (0.102" W x 0.102" H versus 0.106" W x 0.106" H), which remain within standard PCB footprint tolerances for 2-SMD configurations.

Parameter Comparison

Part Number	Manufacturer	Series	Current (A)	Voltage AC (V)	Voltage DC (V)	Response Time	Breaking Capacity	Melting I²t	Product Status	RoHS Status	Packaging
0451007.NR	Littelfuse	NANO²® 451	7	125	125	Fast Blow	50A	10.32	Obsolete	RoHS non-compliant	-
0451007.MRL	Littelfuse	NANO²® 451	7	125	125	Fast Blow	50A	10.32	Active	ROHS3 Compliant	Cut Tape (CT) & Digi-Reel®
0451007.NRL	Littelfuse	NANO²® 451	7	125	125	Fast Blow	50A	10.32	Active	ROHS3 Compliant	Tape & Reel (TR)
0448007.MR	Littelfuse	NANO²® 448	7	125	125	Fast Blow	50A	13.92	Active	ROHS3 Compliant	Tape & Reel (TR)
0453007.MR	Littelfuse	NANO²® 453	7	125	125	Fast Blow	50A	10.32	Active	ROHS3 Compliant	Cut Tape (CT) & Digi-Reel®
0453007.NR	Littelfuse	NANO²® 453	7	125	125	Fast Blow	50A	10.32	Active	ROHS3 Compliant	Tape & Reel (TR)
0476007.MR	Littelfuse	NANO²®476	7	125	125	Fast Blow	100A AC, 300A DC	7.8	Active	ROHS3 Compliant	Tape & Reel (TR)
0476007.MRSN	Littelfuse	NANO²®476	7	125	125	Fast Blow	100A AC, 300A DC	7.8	Active	ROHS3 Compliant	Tape & Reel (TR)
SF-2410FP700T-2	Bourns Inc.	SinglFuse™ SF-2410FP-T	7	125	125	Fast Blow	50A	9.016	Active	ROHS3 Compliant	Tape & Reel (TR)
SF-2410HI700T-2	Bourns Inc.	SinglFuse™ SF-2410HI-T	7	125	125	Fast Blow	50A	100.06	Active	ROHS3 Compliant	Tape & Reel (TR)

Engineering Selection Recommendations

For direct replacement of the obsolete 0451007.NR, the 0451007.MRL and 0451007.NRL are preferred substitutes within the same NANO²® 451 series. Both are active products with ROHS3 compliance and identical electrical characteristics (7 A, 125 V AC/DC, 50A breaking capacity, 10.32 melting I²t). Selection between these two depends on packaging requirements: 0451007.MRL for Cut Tape & Digi-Reel® applications, or 0451007.NRL for Tape & Reel configurations.

The 0453007.MR and 0453007.NR from the NANO²® 453 series provide equivalent performance with ROHS3 compliance and identical electrical ratings. The 0448007.MR from the NANO²® 448 series is functionally compatible but exhibits higher melting I²t (13.92 versus 10.32), which may affect response characteristics in specific circuit applications.

The 0476007.MR and 0476007.MRSN variants offer enhanced breaking capacity (100A AC, 300A DC) and lower melting I²t (7.8), suitable for applications requiring higher fault current handling. These are appropriate only when circuit design permits the altered response profile.

Bourns SinglFuse™ parts (SF-2410FP700T-2, SF-2410HI700T-2) provide cross-manufacturer alternatives with active product status and ROHS3 compliance. The SF-2410FP700T-2 maintains melting I²t characteristics closest to the original (9.016 versus 10.32). The SF-2410HI700T-2 exhibits significantly higher melting I²t (100.06), indicating slower response, and is suitable only for applications where this characteristic is acceptable.

Frequently Asked Questions (FAQ)

Q: Can the 0451007.NR be directly replaced with 0451007.MRL or 0451007.NRL?

A: Yes. Both parts are parametric equivalents within the NANO²® 451 series with identical current rating (7 A), voltage ratings (125 V AC/DC), response time (Fast Blow), breaking capacity (50A), and melting I²t (10.32). The difference is packaging: 0451007.MRL is supplied in Cut Tape & Digi-Reel®, while 0451007.NRL is supplied in Tape & Reel. Both are active products with ROHS3 compliance.

Q: What is the difference between the 0451007.NR and 0476007.MR?

A: Both maintain identical current (7 A) and voltage ratings (125 V AC/DC). The primary differences are breaking capacity (0451007.NR: 50A; 0476007.MR: 100A AC, 300A DC) and melting I²t (0451007.NR: 10.32; 0476007.MR: 7.8). The 0476007.MR is suitable only for applications where higher fault current handling and faster response are required.

Q: Are Bourns SinglFuse™ parts compatible with Littelfuse NANO²® footprints?

A: The Bourns SF-2410FP700T-2 and SF-2410HI700T-2 maintain the 2-SMD, Square End Block package configuration with dimensions 0.240" L x 0.102" W x 0.102" H, compared to Littelfuse dimensions of 0.240" L x 0.106" W x 0.106" H. The 0.004" difference in width and height remains within standard PCB footprint tolerances for surface mount applications. Electrical specifications (7 A, 125 V AC/DC, Fast Blow) are identical.

Q: Which substitute part has the closest melting I²t to the original 0451007.NR?

A: The SF-2410FP700T-2 (melting I²t: 9.016) is closest to the original 0451007.NR (melting I²t: 10.32). The 0451007.MRL and 0451007.NRL maintain exact equivalence (melting I²t: 10.32).

Q: What is the significance of RoHS compliance in selecting a substitute?

A: The original 0451007.NR is RoHS non-compliant. All active substitute parts (0451007.MRL, 0451007.NRL, 0448007.MR, 0453007.MR, 0453007.NR, 0476007.MR, 0476007.MRSN, SF-2410FP700T-2, SF-2410HI700T-2) are ROHS3 compliant, meeting current environmental and regulatory requirements for electronic component manufacturing and assembly.

Q: Can the 0448007.MR be used as a direct substitute?

A: The 0448007.MR is electrically equivalent in current (7 A) and voltage ratings (125 V AC/DC) but differs in melting I²t (13.92 versus 10.32 for the original). This higher melting I²t indicates slower response to overcurrent conditions. Use only if circuit design accommodates the altered thermal response profile.

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