SSQ 5/5K Surface Mount Board Mount Fuse Equivalent & Substitute Parts

Part Overview

The SSQ 5/5K is a 5 A, 125 V AC/DC surface mount board mount fuse manufactured by Bel Fuse Inc. in a 2-SMD, Square End Block package. This part is classified as obsolete, making identification of equivalent and substitute components necessary for ongoing design support and production continuity. Substitute parts must maintain electrical compatibility across current rating, voltage rating, response time, and mechanical package dimensions while meeting applicable regulatory approvals.

Substiute Parts

SSQ 5/5K

Bel Fuse Inc.In Stock: 1123SSQ 5/5K Datasheet

Current PartRFQ

0679L5000-05

Bel Fuse Inc.In Stock: 231520679L5000-05 Datasheet

DirectRFQ

0476005.MR

Littelfuse Inc.In Stock: 25280476005.MR Datasheet

DirectRFQ

0476005.MRSN

Littelfuse Inc.In Stock: 10320476005.MRSN Datasheet

DirectRFQ

0451005.MRSN

Littelfuse Inc.In Stock: 29350451005.MRSN Datasheet

SimilarRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitute parts are classified into two categories based on electrical parameter alignment with the SSQ 5/5K:

Direct Substitutes maintain identical electrical specifications: 5 A current rating, 125 V AC/DC voltage rating, fast blow response, and 2-SMD Square End Block package. These parts are interchangeable at the circuit level without design modification.

• 0679L5000-05 (Bel Fuse Inc., Active): Matches all primary electrical parameters. Differs in melting I²t (5.5 vs. 8.8) and height dimension (2.79 mm vs. 2.54 mm). Includes AEC-Q200 automotive qualification.
• 0451005.MRSN (Littelfuse Inc., Active): Matches all primary electrical parameters. Differs in melting I²t (5.566 vs. 8.8), width/height dimensions (2.69 mm vs. 2.54 mm), and breaking capacity (50 A vs. 50 A AC/300 A DC). Includes CSA, METI, and UR approvals.

Voltage-Rated Substitutes provide enhanced AC voltage rating (250 V AC vs. 125 V AC) while maintaining 5 A current, 125 V DC rating, fast blow response, and 2-SMD package. These parts are suitable for applications requiring higher AC voltage margin.

• 0476005.MR and 0476005.MRSN (Littelfuse Inc., Active): Both are identical variants of the NANO²®476 series. Rated 5 A, 250 V AC/125 V DC. Differ in melting I²t (4 vs. 8.8), dimensions (2.69 mm vs. 2.54 mm), and breaking capacity (100 A AC vs. 50 A AC).

Parameter Comparison

Engineering Selection Recommendations

For Direct Replacement (125 V AC/DC Applications):

Select 0679L5000-05 when AEC-Q200 automotive qualification is required or when sourcing from Bel Fuse Inc. is preferred for supply chain continuity. This part maintains the same voltage rating and current specification as the SSQ 5/5K with active product status and higher inventory availability (23,116 units).

Select 0451005.MRSN when CSA, METI, or UR certifications are required for specific regional compliance. This Littelfuse part maintains identical electrical ratings with active status and adequate inventory (2,922 units).

For Enhanced AC Voltage Margin (250 V AC Applications):

Select 0476005.MR or 0476005.MRSN when circuit design permits 250 V AC rating and higher breaking capacity (100 A AC) is beneficial. Both variants are electrically identical; 0476005.MR has higher inventory (2,461 units vs. 939 units). These parts are suitable for applications requiring additional AC voltage headroom while maintaining 5 A current and 125 V DC rating.

All substitute parts are ROHS3 compliant, MSL Level 1, and operate across the full -55°C to 125°C temperature range.

Frequently Asked Questions (FAQ)

Q: Can 0679L5000-05 be used as a direct replacement for SSQ 5/5K?

A: Yes. Both parts share identical current rating (5 A), voltage rating (125 V AC/DC), response time (fast blow), and package type (2-SMD, Square End Block). The 0679L5000-05 has a slightly greater height (2.79 mm vs. 2.54 mm) and lower melting I²t (5.5 vs. 8.8), which must be verified against circuit thermal design requirements.

Q: What is the difference between 0476005.MR and 0476005.MRSN?

A: These are identical electrical and mechanical variants of the NANO²®476 series. The difference is packaging designation; both are rated 5 A, 250 V AC/125 V DC with identical dimensions and performance characteristics. Selection between them depends on supplier availability and procurement requirements.

Q: Can 0476005.MR/MRSN replace SSQ 5/5K in a 125 V AC circuit?

A: Yes, with design margin consideration. The 0476005 series is rated 250 V AC, providing 2× voltage margin over the SSQ 5/5K's 125 V AC rating. However, the melting I²t is significantly lower (4 vs. 8.8), which affects thermal response characteristics. Circuit thermal analysis is required to confirm compatibility.

Q: Are all substitute parts RoHS3 compliant?

A: Yes. All listed substitute parts (0679L5000-05, 0451005.MRSN, 0476005.MR, and 0476005.MRSN) are ROHS3 compliant with MSL Level 1 moisture sensitivity rating.

Q: Which substitute has the best availability?

A: 0679L5000-05 has the highest inventory at 23,116 units. 0451005.MRSN has 2,922 units, and 0476005.MR has 2,461 units. 0476005.MRSN has the lowest inventory at 939 units.

Q: What certifications does each substitute carry?

A: 0679L5000-05 carries AEC-Q200 and cURus approvals. 0451005.MRSN carries CSA, METI, and UR approvals. 0476005.MR and 0476005.MRSN carry cURus approval. The original SSQ 5/5K carries CE, CSA, and cULus approvals. Verify that selected substitute meets all required regional and application-specific certifications.