Littelfuse 025501.5M Equivalent & Substitute Parts

Part Overview

The Littelfuse 025501.5M is a 1.5 A board mount axial fuse rated for 125 V AC/DC operation, designed for through-hole PCB mounting in the PICO® 255 series. This component is classified as obsolete, making identification of compatible substitutes essential for ongoing maintenance, repair, and legacy system support. The part's fast-blow response characteristic and 50 A AC / 300 A DC breaking capacity define its application scope in circuit protection.

Substiute Parts

025501.5M

Littelfuse Inc.In Stock: 720025501.5M Datasheet

Current PartRFQ

025101.5MXL

Littelfuse Inc.In Stock: 1550025101.5MXL Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the 025501.5M is determined by strict equivalence across the following electrical and mechanical parameters:

• Current Rating: 1.5 A (exact match required)
• Voltage Rating: 125 V AC and 125 V DC (exact match required)
• Response Time: Fast Blow (exact match required)
• Fuse Type: Board Mount, Cartridge Style Excluded (exact match required)
• Mounting Type: Through Hole (exact match required)
• Package / Case: Axial (exact match required)
• Breaking Capacity: 50 A AC / 300 A DC (exact match required)

The Littelfuse 025101.5MXL meets all mandatory electrical and mechanical substitution criteria. While dimensional and compliance differences exist between the obsolete 025501.5M and its active substitute, the core functional parameters remain equivalent for circuit protection applications.

Parameter Comparison

Engineering Selection Recommendations

The Littelfuse 025101.5MXL is the direct functional equivalent for the obsolete 025501.5M. Both components share identical electrical ratings, response characteristics, and breaking capacity specifications required for circuit protection in 125 V AC/DC applications.

The 025101.5MXL offers the following advantages for new designs and legacy replacements:

• Active product status ensures ongoing availability and supply chain continuity
• ROHS3 compliance supports modern manufacturing and environmental regulations
• Extended approval certifications (CSA, cURus, PSE, TUV) provide broader global market acceptance
• Operating temperature range of -55°C to 125°C accommodates wider environmental conditions
• Specified DC cold resistance (0.0823 Ohms) and melting I²t (0.587) provide measurable performance data

Physical dimensions differ slightly (0.110" diameter vs. 0.095" diameter), requiring verification of PCB layout compatibility during board redesign or retrofit applications.

Frequently Asked Questions (FAQ)

Q: Can the 025101.5MXL be used as a direct replacement for the 025501.5M in existing designs?

A: Yes, provided PCB through-hole spacing accommodates the 0.110" diameter lead of the 025101.5MXL. The 025501.5M uses 0.095" diameter leads. Verify mechanical fit before implementation.

Q: What is the significance of the different approval agencies listed for each part?

A: The 025501.5M carries CSA and UL approvals. The 025101.5MXL carries CSA, cURus, PSE, and TUV approvals. Both meet the minimum certification requirements for 125 V AC/DC fuse applications. The substitute offers broader international regulatory acceptance.

Q: Why is the 025501.5M classified as obsolete?

A: The PICO® 255 series has been superseded by the PICO® II 251 series, of which the 025101.5MXL is a member. Littelfuse has transitioned production to the newer series.

Q: Are there electrical performance differences between the two parts?

A: Both parts are specified as fast-blow fuses with identical current, voltage, and breaking capacity ratings. The 025101.5MXL provides additional performance data (melting I²t and DC cold resistance) not specified for the obsolete 025501.5M.

Q: What is the impact of RoHS compliance differences?

A: The 025501.5M is RoHS non-compliant; the 025101.5MXL is ROHS3 compliant. For new product designs subject to RoHS regulations, the 025101.5MXL is required. For legacy system maintenance where RoHS compliance is not mandated, either part meets functional requirements.

Q: How do packaging differences affect component selection?

A: The 025501.5M is specified with "-" packaging; the 025101.5MXL is supplied in bulk packaging. For procurement and inventory management, verify packaging requirements with your supplier.