Littelfuse 0251001.M PICO® II 251 Board Mount Fuse Equivalent & Substitute Parts

Part Overview

The Littelfuse 0251001.M is a 1 A, 125 V AC/DC board mount axial fuse from the PICO® II 251 series, designed for through-hole mounting 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 approval certifications to ensure direct interchangeability in circuit protection applications.

Substiute Parts

0251001.M

Littelfuse Inc.In Stock: 9910251001.M Datasheet

Current PartRFQ

0251001.MXL

LittelfuseIn Stock: 12600251001.MXL Datasheet

Parametric EquivalentRFQ

0251001.VXL

Littelfuse Inc.In Stock: 9930251001.VXL Datasheet

Parametric EquivalentRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitute parts for the 0251001.M are identified based on strict equivalence across all critical electrical and mechanical parameters. The substitution criteria are:

• Current Rating: 1 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)
• Package / Case: Axial (exact match required)
• Physical Dimensions: 0.110" Dia x 0.280" L (exact match required)
• Breaking Capacity: 50 A AC, 300 A DC (exact match required)
• Melting I²t: 0.256 (exact match required)
• DC Cold Resistance: 0.128 Ohms (exact match required)
• Approval Agencies: CCC, CSA, cURus, PSE, TUV (exact match required)

Both substitute parts listed below meet all these criteria and are classified as active products, making them suitable replacements for the obsolete 0251001.M.

Parameter Comparison

Engineering Selection Recommendations

Both 0251001.MXL and 0251001.VXL are direct electrical and mechanical equivalents to the obsolete 0251001.M. Selection between these two active alternatives should be based on the following factors:

RoHS Compliance: Both substitute parts are ROHS3 compliant, whereas the main part is RoHS non-compliant. For applications subject to RoHS regulations, either substitute part is suitable.

Product Status: Both substitute parts carry active product status, ensuring ongoing availability and supply chain continuity compared to the obsolete main part.

Packaging: Both substitute parts are supplied in bulk packaging, which may differ from the original packaging configuration of the main part.

Regulatory Certifications: All three parts maintain identical approval certifications (CCC, CSA, cURus, PSE, TUV), confirming compliance with international safety standards.

REACH Status: Both substitute parts are REACH unaffected, providing additional regulatory assurance for European applications.

Frequently Asked Questions (FAQ)

Q: Can 0251001.MXL and 0251001.VXL be used interchangeably with 0251001.M?

A: Yes. Both substitute parts are parametric equivalents with identical electrical ratings (1 A, 125 V AC/DC), response time (fast blow), mechanical dimensions (0.110" Dia x 0.280" L), and approval certifications. They are direct replacements for through-hole board mount applications.

Q: What is the primary reason to transition from 0251001.M to a substitute part?

A: The 0251001.M is classified as obsolete. The substitute parts 0251001.MXL and 0251001.VXL are active products with confirmed ongoing availability, making them the appropriate choice for new designs and production continuity.

Q: Are there differences in RoHS compliance between the main part and substitutes?

A: Yes. The main part 0251001.M is RoHS non-compliant, while both substitute parts (0251001.MXL and 0251001.VXL) are ROHS3 compliant. For applications requiring RoHS compliance, the substitute parts are the correct selection.

Q: Do the substitute parts have the same breaking capacity as the main part?

A: Yes. All three parts have identical breaking capacity ratings of 50 A AC and 300 A DC at rated voltage, ensuring equivalent circuit protection performance.

Q: What is the difference between 0251001.MXL and 0251001.VXL?

A: Both parts are parametric equivalents with identical electrical and mechanical specifications. The designation difference (MXL vs. VXL) reflects internal Littelfuse product line variations but does not affect functional interchangeability in circuit applications.

Q: Are the substitute parts suitable for the same operating temperature range?

A: Yes. All three parts operate across the identical temperature range of -55°C to 125°C, confirming thermal compatibility for equivalent applications.

Q: What certifications do the substitute parts carry?

A: Both substitute parts maintain the same approval certifications as the main part: CCC, CSA, cURus, PSE, and TUV. Additionally, both are REACH unaffected, providing regulatory assurance for international markets.