SSQ 12 Equivalent & Substitute Parts Reference

Part Overview

The SSQ 12 is a 12 A surface mount board mount fuse manufactured by Bel Fuse Inc., rated for 125 V AC and 86 V DC operation. This component is classified as obsolete, making equivalent substitute parts necessary for new designs and ongoing production requirements. The SSQ 12 features fast-blow response characteristics and is packaged in a 2-SMD square end block configuration suitable for automated assembly processes.

Substiute Parts

SSQ 12

Bel Fuse Inc.In Stock: 744SSQ 12 Datasheet

Current PartRFQ

0679L9120-01

Bel Fuse Inc.In Stock: 15040679L9120-01 Datasheet

DirectRFQ

0451012.MRL

Littelfuse Inc.In Stock: 1001370451012.MRL Datasheet

SimilarRFQ

0453012.MR

Littelfuse Inc.In Stock: 62130453012.MR Datasheet

SimilarRFQ

0476012.MR

Littelfuse Inc.In Stock: 10870476012.MR Datasheet

SimilarRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitute parts for the SSQ 12 are grouped based on the following critical electrical and mechanical parameters:

Primary Substitution Criteria:

• Current Rating: 12 A (exact match required)
• Mounting Type: Surface Mount (exact match required)
• Package / Case: 2-SMD, Square End Block (exact match required)
• Response Time: Fast Blow (exact match required)
• Operating Temperature Range: -55°C to 125°C (exact match required)

Voltage Rating Compatibility: Substitutes must meet or exceed the SSQ 12 voltage requirements of 125 V AC and 86 V DC. Parts rated for 125 V AC / 125 V DC exceed the original specification and are acceptable. Parts rated for 65 V AC / 65 V DC do not meet the AC voltage requirement and are limited to applications where circuit voltage does not exceed 65 V AC.

Compliance and Certification: All substitute parts maintain ROHS3 compliance and operate within the specified temperature range. Approval agencies vary by part number but include recognized standards bodies (cULus, AEC-Q200, CSA, UL, cURus).

Parameter Comparison

Engineering Selection Recommendations

Full Voltage Equivalents (Recommended for Direct Replacement):

The 0679L9120-01 (Bel Fuse Inc.) and 0476012.MR (Littelfuse Inc. NANO²® 476) are direct functional equivalents. Both are rated for 125 V AC / 125 V DC, meeting or exceeding the SSQ 12 voltage specification. Both parts are active products with current manufacturing status, ensuring long-term availability. The 0679L9120-01 maintains the same manufacturer lineage as the obsolete SSQ 12. The 0476012.MR offers enhanced breaking capacity (100 A AC, 300 A DC) and lower melting I²t (20.635), providing improved performance characteristics.

Reduced Voltage Substitutes (Application-Dependent):

The 0451012.MRL and 0453012.MR (both Littelfuse Inc. NANO²® series) are rated for 65 V AC / 65 V DC. These parts are suitable only for applications where the circuit voltage does not exceed 65 V AC. Both maintain the required 12 A current rating, fast-blow response, and surface mount 2-SMD package configuration. These options offer the highest inventory availability and lowest DC cold resistance (0.0049 Ohms).

Compliance Considerations:

All substitute parts maintain ROHS3 compliance and operate within the -55°C to 125°C temperature range. The 0679L9120-01 carries AEC-Q200 certification, suitable for automotive applications. The 0476012.MR carries cURus certification. The 0451012.MRL and 0453012.MR carry CSA and UL certifications. Select the substitute part based on application-specific compliance requirements.

Frequently Asked Questions (FAQ)

Q: Can the 0451012.MRL or 0453012.MR be used as direct replacements for the SSQ 12?

A: These parts are suitable only if the application circuit voltage does not exceed 65 V AC. The SSQ 12 is rated for 125 V AC, and these substitutes are rated for 65 V AC / 65 V DC. Using a lower-voltage fuse in a higher-voltage circuit creates a safety hazard. For circuits operating at 125 V AC, use the 0679L9120-01 or 0476012.MR.

Q: What is the difference between the 0679L9120-01 and 0476012.MR?

A: Both parts are rated for 125 V AC / 125 V DC and are suitable for direct replacement. The 0476012.MR offers higher breaking capacity (100 A AC, 300 A DC versus 50 A AC, 300 A DC) and lower melting I²t (20.635 versus 38.9). The 0679L9120-01 is packaged in Tape & Reel format, while the 0476012.MR is packaged in Cut Tape format. Select based on procurement and assembly requirements.

Q: Are there dimensional compatibility concerns with substitute parts?

A: The SSQ 12 measures 6.10 x 2.54 x 2.54 mm. The 0679L9120-01 measures 6.10 x 2.54 x 2.79 mm (0.25 mm height increase). The Littelfuse NANO²® parts (0451012.MRL, 0453012.MR, 0476012.MR) measure 6.10 x 2.69 x 2.69 mm (0.15 mm width and height increase). These dimensional variations are within typical PCB assembly tolerances for surface mount components. Verify PCB footprint clearances before design implementation.

Q: Why is the SSQ 12 listed as obsolete?

A: The SSQ 12 is no longer manufactured by Bel Fuse Inc. All substitute parts listed are active products with current manufacturing status, ensuring availability for new designs and production continuity.

Q: What packaging formats are available for these substitute parts?

A: The 0679L9120-01 is available in Tape & Reel (TR) format. The 0451012.MRL and 0453012.MR are available in Tape & Reel (TR) format. The 0476012.MR is available in Cut Tape (CT) format. Select packaging based on assembly equipment and procurement volume requirements.