Littelfuse 0251007.MRT1 Equivalent & Substitute Parts

Part Overview

The Littelfuse 0251007.MRT1 is a 7 A, 125 V AC/DC board mount axial fuse from the PICO® II 251 series. This component is classified as obsolete, which necessitates identification of active equivalent parts for ongoing design support and procurement. The part is designed for through-hole mounting applications requiring fast-blow response characteristics and is approved by CSA, cURus, and TUV standards.

Key Parameters

Parameter	Value
Current Rating	7 A
Voltage Rating (AC)	125 V
Voltage Rating (DC)	125 V
Response Time	Fast Blow
Mounting Type	Through Hole
Fuse Type	Board Mount (Cartridge Style Excluded)
Package / Case	Axial
Size / Dimension	0.110" Dia x 0.280" L (2.80mm x 7.11mm)
DC Cold Resistance	0.0107 Ohms
Melting I²t	10.4
Breaking Capacity @ Rated Voltage	50A AC, 300A DC
Operating Temperature Range	-55°C ~ 125°C
Approval Agencies	CSA, cURus, TUV

Substitute Part Grouping Explanation

Substitution of the obsolete 0251007.MRT1 is determined by strict equivalence across the following critical parameters:

Current Rating: 7 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: Through Hole (exact match required)
Fuse Type: Board Mount (Cartridge Style Excluded) (exact match required)
Physical Dimensions: 0.110" Dia x 0.280" L (exact match required)
DC Cold Resistance: 0.0107 Ohms (exact match required)
Melting I²t: 10.4 (exact match required)
Approval Agencies: CSA, cURus, TUV (exact match required)

Littelfuse parametric equivalents within the PICO® II 251 series differ only in packaging format (Cut Tape, Tape & Reel) and product status (Active vs. Obsolete). The SCHURTER 7010.7140.13 represents a direct manufacturer alternative with compatible electrical specifications but differs in physical dimensions and melting I²t characteristics.

Parameter Comparison

Part Number	Manufacturer	Current Rating	Voltage (AC/DC)	Response Time	Package Type	Dimensions	Melting I²t	Breaking Capacity (AC)	Product Status	RoHS Status
0251007.MRT1	Littelfuse	7 A	125 V / 125 V	Fast Blow	Axial	0.110" x 0.280"	10.4	50 A	Obsolete	Non-compliant
0251007.HAT1L	Littelfuse	7 A	125 V / 125 V	Fast Blow	Cut Tape (CT)	0.110" x 0.280"	10.4	50 A	Active	ROHS3 Compliant
0251007.MAT1L	Littelfuse	7 A	125 V / 125 V	Fast Blow	Cut Tape (CT)	0.110" x 0.280"	10.4	50 A	Active	ROHS3 Compliant
0251007.MRT1L	Littelfuse	7 A	125 V / 125 V	Fast Blow	Cut Tape (CT)	0.110" x 0.280"	10.4	50 A	Active	ROHS3 Compliant
0251007.NRT1JL	Littelfuse	7 A	125 V / 125 V	Fast Blow	Tape & Reel (TR)	0.110" x 0.280"	10.4	50 A	Active	ROHS3 Compliant
0251007.NRT1L	Littelfuse	7 A	125 V / 125 V	Fast Blow	Cut Tape (CT)	0.110" x 0.280"	10.4	50 A	Active	ROHS3 Compliant
0251007.PARJL	Littelfuse	7 A	125 V / 125 V	Fast Blow	Tape & Reel (TR)	0.110" x 0.280"	10.4	50 A	Active	ROHS3 Compliant
7010.7140.13	SCHURTER	7 A	125 V / 125 V	Fast Blow	Cartridge, Non-Standard (Axial)	0.093" x 0.315"	13	300 A	Active	ROHS3 Compliant

Engineering Selection Recommendations

For applications currently using the obsolete 0251007.MRT1, the following selection criteria apply:

Littelfuse PICO® II 251 Series (Preferred): Parts 0251007.HAT1L, 0251007.MAT1L, 0251007.MRT1L, 0251007.NRT1JL, 0251007.NRT1L, and 0251007.PARJL provide complete electrical and mechanical equivalence. All are active products with ROHS3 compliance and REACH unaffected status. Selection among these parts depends on packaging requirements: Cut Tape (CT) for manual assembly or small-volume production, or Tape & Reel (TR) for automated assembly processes. Inventory availability varies, with 0251007.NRT1L offering the highest stock level at 175,060 pieces.

SCHURTER 7010.7140.13 (Alternative): This part maintains electrical compatibility (7 A, 125 V AC/DC, Fast Blow) but differs in physical dimensions (0.093" Dia x 0.315" L versus 0.110" Dia x 0.280" L) and melting I²t (13 versus 10.4). The higher breaking capacity (300 A) and different thermal characteristics require PCB layout verification before implementation. This option is suitable only when mechanical constraints permit the larger form factor.

All recommended substitutes maintain CSA, cURus, and TUV approvals, ensuring regulatory compliance for existing applications.

Frequently Asked Questions (FAQ)

Q: Can 0251007.NRT1L be used as a direct replacement for 0251007.MRT1?

A: Yes. Both parts share identical electrical specifications (7 A, 125 V AC/DC, Fast Blow response), physical dimensions (0.110" Dia x 0.280" L), and thermal characteristics (Melting I²t 10.4). The primary difference is product status (Active versus Obsolete) and packaging format (Cut Tape versus unspecified). Regulatory approvals (CSA, cURus, TUV) are equivalent.

Q: What is the difference between Cut Tape (CT) and Tape & Reel (TR) packaging?

A: Cut Tape packaging supplies individual components on tape segments suitable for manual assembly or low-volume pick-and-place operations. Tape & Reel packaging provides continuous reels for high-speed automated assembly equipment. Electrical and mechanical specifications are identical; packaging selection depends on production volume and assembly methodology.

Q: Is the SCHURTER 7010.7140.13 a suitable replacement?

A: The SCHURTER part maintains electrical equivalence but introduces mechanical differences. Physical dimensions differ (0.093" Dia x 0.315" L versus 0.110" Dia x 0.280" L), and melting I²t is higher (13 versus 10.4). PCB footprint and thermal design verification are required before substitution. This part is suitable only when mechanical constraints permit the alternative form factor.

Q: Why is RoHS compliance status different between the main part and substitutes?

A: The obsolete 0251007.MRT1 predates RoHS3 compliance requirements and is listed as non-compliant. All active substitutes (0251007.HAT1L, 0251007.MAT1L, 0251007.MRT1L, 0251007.NRT1JL, 0251007.NRT1L, 0251007.PARJL) are manufactured to current ROHS3 standards. For new designs or compliance-sensitive applications, active substitutes are required.

Q: Are all Littelfuse substitutes interchangeable in existing designs?

A: Yes, for electrical and thermal performance. All Littelfuse PICO® II 251 series substitutes (0251007.HAT1L, 0251007.MAT1L, 0251007.MRT1L, 0251007.NRT1JL, 0251007.NRT1L, 0251007.PARJL) are parametrically identical and share the same PCB footprint. Packaging format selection (Cut Tape or Tape & Reel) affects procurement and assembly processes only, not circuit performance.

Q: What inventory considerations apply to these substitutes?

A: Inventory levels vary significantly. 0251007.NRT1L offers the highest availability (175,060 pieces), while 0251007.HAT1L and 0251007.PARJL have lower stock (1,012 and 1,044 pieces respectively). For high-volume production, 0251007.NRT1L is recommended. For immediate small-quantity requirements, multiple sources should be evaluated based on current availability.

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