Littelfuse 0251.630M Equivalent & Substitute Parts

Part Overview

The Littelfuse 0251.630M is a 630 mA board mount axial fuse rated for 125 V AC/DC operation. Designed for through-hole mounting in the PICO® II 251 series, this component provides fast-blow protection in electronic circuits. The part is currently classified as obsolete, making identification of active equivalent parts essential for ongoing design support and procurement continuity.

Substiute Parts

0251.630M

Littelfuse Inc.In Stock: 9530251.630M Datasheet

Current PartRFQ

0251.630MXL

Littelfuse Inc.In Stock: 12550251.630MXL Datasheet

DirectRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the Littelfuse 0251.630M is determined by strict equivalence across the following electrical and mechanical parameters:

• Current Rating: 630 mA (exact match required)
• Voltage Rating: 125 V AC and 125 V DC (both must match)
• Response Time: Fast Blow (characteristic must match)
• Mounting Type: Through Hole (physical installation requirement)
• Fuse Type: Board Mount, Axial configuration (form factor requirement)
• Breaking Capacity: 50A AC, 300A DC (fault protection specification)
• Operating Temperature Range: -55°C to 125°C (environmental specification)
• Physical Dimensions: 0.110" Dia x 0.280" L (PCB layout constraint)
• DC Cold Resistance: 0.205 Ohms (electrical performance)
• Melting I²t: 0.08 (thermal energy specification)

The Littelfuse 0251.630MXL meets all these criteria and qualifies as a direct substitute.

Parameter Comparison

Engineering Selection Recommendations

The Littelfuse 0251.630MXL is the direct substitute for the obsolete 0251.630M. Both parts are manufactured by Littelfuse within the same PICO® II 251 series and maintain identical electrical and mechanical specifications across all critical parameters.

The primary distinction between the two parts is product status and regulatory compliance. The 0251.630M is obsolete and RoHS non-compliant, while the 0251.630MXL is active and ROHS3 compliant. For new designs or ongoing production requiring RoHS compliance, the 0251.630MXL is the appropriate selection. Both parts carry CSA and cURus approvals and are suitable for applications requiring 630 mA protection at 125 V AC/DC with fast-blow response characteristics.

Frequently Asked Questions (FAQ)

Q: Can the 0251.630MXL be used as a direct replacement for the 0251.630M?

A: Yes. The 0251.630MXL is electrically and mechanically identical to the 0251.630M across all specified parameters, including current rating, voltage rating, response time, dimensions, and breaking capacity. Both parts are from the same manufacturer and series.

Q: What is the difference between the 0251.630M and 0251.630MXL?

A: The primary differences are product status and RoHS compliance. The 0251.630M is obsolete and RoHS non-compliant, while the 0251.630MXL is active and ROHS3 compliant. All electrical and mechanical specifications are identical.

Q: Are there any packaging differences between these parts?

A: The 0251.630M is available in standard packaging, while the 0251.630MXL is supplied in bulk packaging. This does not affect the component's electrical or mechanical performance.

Q: Will the 0251.630MXL fit in the same PCB footprint as the 0251.630M?

A: Yes. Both parts have identical physical dimensions of 0.110" Dia x 0.280" L (2.80mm x 7.11mm) and use the same axial through-hole mounting configuration.

Q: What certifications do these fuses carry?

A: Both the 0251.630M and 0251.630MXL are approved by CSA and cURus, meeting recognized safety standards for fuse components.

Q: Is the 0251.630MXL suitable for new product designs?

A: Yes. The 0251.630MXL is an active product with ROHS3 compliance, making it appropriate for new designs and ongoing production applications.