SSQ 630/1K Equivalent & Substitute Parts

Part Overview

The SSQ 630/1K is a 630 mA, 125 V AC/DC surface mount fuse manufactured by Bel Fuse Inc. in a 2-SMD, square end block package. This component is classified as obsolete, making identification of functionally equivalent alternatives essential for ongoing design support and procurement continuity. Substitute parts must maintain identical electrical ratings, mechanical compatibility, and approval certifications to ensure reliable operation in existing circuit designs.

Substiute Parts

SSQ 630/1K

Bel Fuse Inc.In Stock: 923SSQ 630/1K Datasheet

Current PartRFQ

0451.630MRSN

Littelfuse Inc.In Stock: 6960451.630MRSN Datasheet

SimilarRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the SSQ 630/1K is determined by strict alignment of the following parameters:

• Current Rating: 630 mA (exact match required)
• Voltage Rating: 125 V AC minimum; DC rating must support 125 V or higher
• Response Time: Fast Blow (required for circuit protection coordination)
• Mounting Type: Surface Mount (PCB assembly compatibility)
• Package / Case: 2-SMD, Square End Block (physical and electrical footprint compatibility)
• Operating Temperature Range: -55°C ~ 125°C minimum (thermal environment compatibility)
• RoHS Compliance: ROHS3 Compliant (regulatory requirement)

The substitute part 0451.630MRSN (Littelfuse Inc., NANO²® 451 series) meets all mandatory substitution criteria and is classified as Active, providing long-term availability and design support.

Parameter Comparison

Engineering Selection Recommendations

The 0451.630MRSN is the qualified substitute for the obsolete SSQ 630/1K based on the following engineering criteria:

• Electrical equivalence: Identical current rating (630 mA), voltage rating (125 V AC), response time (Fast Blow), and operating temperature range (-55°C ~ 125°C)
• Mechanical compatibility: Matching 2-SMD, square end block package with equivalent footprint dimensions (length 6.10 mm identical; width and height within 0.15 mm tolerance)
• Regulatory compliance: Both parts are ROHS3 compliant with MSL 1 rating
• Product availability: The substitute is classified as Active, ensuring procurement continuity and long-term design support
• Approval certifications: Both parts carry recognized safety approvals (CSA, UR for the substitute; CE, CSA, cULus for the original)

Frequently Asked Questions (FAQ)

Q: Can the 0451.630MRSN be used as a direct replacement for the SSQ 630/1K?

A: Yes. Both parts share identical current rating (630 mA), voltage rating (125 V AC), response time (Fast Blow), mounting type (Surface Mount), package style (2-SMD, Square End Block), and operating temperature range (-55°C ~ 125°C). Physical dimensions are equivalent within standard manufacturing tolerances.

Q: What is the significance of the "Fast Blow" response time?

A: Fast Blow fuses are designed to interrupt circuits rapidly when current exceeds the rated value. This characteristic must be preserved in any substitute to maintain circuit protection coordination and prevent nuisance trips or delayed fault clearing.

Q: Are there dimensional differences between these parts?

A: The SSQ 630/1K measures 0.240" L x 0.100" W x 0.100" H (6.10mm x 2.54mm x 2.54mm). The 0451.630MRSN measures 0.240" L x 0.106" W x 0.106" H (6.10mm x 2.69mm x 2.69mm). The length is identical; width and height differ by 0.06 mm (0.15 mm tolerance), which is within standard PCB assembly specifications for 2-SMD components.

Q: Why is product status important in substitution?

A: The SSQ 630/1K is obsolete, meaning Bel Fuse Inc. no longer manufactures or supports this part. The 0451.630MRSN is Active, ensuring continued availability, technical support, and compliance with current manufacturing standards.

Q: What compliance certifications should I verify?

A: Both parts are ROHS3 compliant and carry recognized safety approvals. The original part holds CE, CSA, and cULus certifications. The substitute holds CSA and UR certifications. Verify that the substitute's approval set meets your application's regulatory requirements before final design release.