Littelfuse 025102.5M PICO® II 251 Board Mount Fuse - Equivalent & Substitute Parts

Part Overview

The Littelfuse 025102.5M is a 2.5 A, 125 V AC/DC board mount axial fuse from the PICO® II 251 series, designed for through-hole PCB applications. This part is classified as obsolete, making identification of active equivalent alternatives essential for ongoing production and maintenance requirements. Substitute parts must maintain identical electrical ratings, mechanical dimensions, and performance characteristics to ensure direct compatibility in existing circuit designs.

Key Parameters

Parameter	Specification
Current Rating	2.5 A
Voltage Rating (AC)	125 V
Voltage Rating (DC)	125 V
Response Time	Fast Blow
Mounting Type	Through Hole
Package Style	Axial
Physical Dimensions	0.110" Dia × 0.280" L (2.80mm × 7.11mm)
Breaking Capacity	50 A AC, 300 A DC
DC Cold Resistance	0.036 Ohms
Melting I²t	0.721
Operating Temperature Range	-55°C to 125°C
Approval Agencies	CCC, CSA, cURus, PSE, TUV

Substitute Part Grouping Explanation

Substitution eligibility for the 025102.5M is determined by strict equivalence across the following critical parameters:

Current Rating: 2.5 A (exact match required)
Voltage Ratings: 125 V AC and 125 V DC (exact match required)
Response Time: Fast Blow (exact match required)
Mounting Configuration: Through Hole, Axial package (exact match required)
Physical Dimensions: 0.110" Dia × 0.280" L (exact match required)
Breaking Capacity: 50 A AC, 300 A DC (exact match required)
DC Cold Resistance: 0.036 Ohms (exact match required)
Melting I²t: 0.721 (exact match required)

The two identified substitutes—025102.5MXL and 025102.5VXL—meet all electrical and mechanical equivalence criteria. Both parts are manufactured by Littelfuse Inc. within the same PICO® II 251 series and maintain identical performance specifications. The primary distinction between these substitutes and the original part is product status: both alternatives are classified as active, whereas the 025102.5M is obsolete.

Parameter Comparison

Parameter	025102.5M (Original)	025102.5MXL (Substitute)	025102.5VXL (Substitute)
Manufacturer	Littelfuse Inc.	Littelfuse Inc.	Littelfuse Inc.
Series	PICO® II 251	PICO® II 251	PICO® II 251
Current Rating	2.5 A	2.5 A	2.5 A
Voltage Rating (AC)	125 V	125 V	125 V
Voltage Rating (DC)	125 V	125 V	125 V
Response Time	Fast Blow	Fast Blow	Fast Blow
Mounting Type	Through Hole	Through Hole	Through Hole
Package Style	Axial	Axial	Axial
Physical Dimensions	0.110" Dia × 0.280" L (2.80mm × 7.11mm)	0.110" Dia × 0.280" L (2.80mm × 7.11mm)	0.110" Dia × 0.280" L (2.80mm × 7.11mm)
Breaking Capacity	50 A AC, 300 A DC	50 A AC, 300 A DC	50 A AC, 300 A DC
DC Cold Resistance	0.036 Ohms	0.036 Ohms	0.036 Ohms
Melting I²t	0.721	0.721	0.721
Operating Temperature Range	-55°C to 125°C	-55°C to 125°C	-55°C to 125°C
Approval Agencies	CCC, CSA, cURus, PSE, TUV	CCC, CSA, cURus, PSE, TUV	CCC, CSA, cURus, PSE, TUV
Product Status	Obsolete	Active	Active
RoHS Compliance	RoHS non-compliant	ROHS3 Compliant	ROHS3 Compliant

Engineering Selection Recommendations

Both 025102.5MXL and 025102.5VXL are direct parametric equivalents to the 025102.5M and are suitable for replacement in applications requiring a 2.5 A, 125 V AC/DC board mount axial fuse. Selection between the two active substitutes should be based on availability and supply chain considerations, as both maintain identical electrical and mechanical specifications.

The transition from the obsolete 025102.5M to either active substitute is supported by:

Identical electrical performance across all rated parameters
Matching mechanical form factor and PCB footprint compatibility
Equivalent breaking capacity and thermal characteristics
Maintained regulatory approvals (CCC, CSA, cURus, PSE, TUV)
Enhanced RoHS3 compliance status in both substitutes

Frequently Asked Questions (FAQ)

Q: Can 025102.5MXL and 025102.5VXL be used interchangeably with 025102.5M?

A: Yes. Both substitutes are parametric equivalents with identical current ratings, voltage ratings, response time, physical dimensions, and performance characteristics. Direct PCB substitution is supported without circuit modification.

Q: What is the difference between 025102.5MXL and 025102.5VXL?

A: Both parts are electrically and mechanically identical. The difference lies in packaging designation (MXL vs. VXL suffix) and potential supply chain availability. Selection should be based on component procurement and inventory requirements.

Q: Why is the original 025102.5M classified as obsolete?

A: The 025102.5M has been superseded by active alternatives within the PICO® II 251 series. The substitute parts offer improved RoHS3 compliance and continued manufacturing support.

Q: Are there any compatibility concerns when replacing 025102.5M with the substitutes?

A: No compatibility concerns exist. The substitutes maintain the same axial through-hole package, identical physical dimensions (0.110" Dia × 0.280" L), and equivalent electrical performance. Direct PCB mounting without modification is supported.

Q: Do the substitute parts maintain the same regulatory approvals?

A: Yes. Both 025102.5MXL and 025102.5VXL carry the same approval agencies: CCC, CSA, cURus, PSE, and TUV, ensuring compliance with the same standards as the original part.

Q: What is the significance of RoHS3 compliance in the substitutes?

A: The substitute parts are ROHS3 compliant, whereas the original 025102.5M is RoHS non-compliant. This reflects updated environmental and regulatory standards and is beneficial for applications subject to RoHS requirements.

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