SSQ 6.3/5K Equivalent & Substitute Parts

Part Overview

The SSQ 6.3/5K is a 6.3 A surface mount board mount fuse manufactured by Bel Fuse Inc., rated for 125 V AC/DC operation with fast blow response characteristics. This component is classified as obsolete, making equivalent and substitute parts necessary for ongoing design support and production continuity. The part is housed in a 2-SMD square end block package and meets ROHS3 compliance requirements.

Substiute Parts

SSQ 6.3/5K

Bel Fuse Inc.In Stock: 876SSQ 6.3/5K Datasheet

Current PartRFQ

0679L6300-05

Bel Fuse Inc.In Stock: 256660679L6300-05 Datasheet

DirectRFQ

047606.3MR

Littelfuse Inc.In Stock: 827047606.3MR Datasheet

DirectRFQ

047606.3MRSN

Littelfuse Inc.In Stock: 2305047606.3MRSN Datasheet

DirectRFQ

045106.3MRSN

Littelfuse Inc.In Stock: 3222045106.3MRSN Datasheet

SimilarRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the SSQ 6.3/5K is determined by strict alignment of the following parameters:

• Current Rating: 6.3 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: Surface Mount (exact match required)
• Package / Case: 2-SMD, Square End Block (exact match required)
• Operating Temperature Range: -55°C ~ 125°C (exact match required)
• RoHS Status: ROHS3 Compliant (exact match required)

All substitute parts listed meet these core electrical and mechanical parameters. Variations in breaking capacity, melting I²t, physical dimensions within tolerance, DC cold resistance, and approval agencies do not disqualify substitution eligibility when all primary parameters align.

Parameter Comparison

Engineering Selection Recommendations

Direct Substitutes (Bel Fuse Inc. Series): The 0679L6300-05 from Bel Fuse Inc. is the primary direct substitute for the obsolete SSQ 6.3/5K. Both components share identical electrical ratings and mounting specifications. The 0679L6300-05 carries active product status and holds AEC-Q200 and cURus certifications, providing enhanced reliability documentation for automotive and industrial applications.

Cross-Manufacturer Substitutes (Littelfuse Inc. NANO²® Series): The 047606.3MR and 047606.3MRSN from Littelfuse Inc. meet all core electrical and mechanical parameters. Both are active products with cURus certification. The 047606.3MRSN offers higher breaking capacity (100 A AC versus 50 A AC) compared to the main part, providing additional margin in fault current handling. The 047606.3MR is available in standard Tape & Reel packaging.

Alternative Substitute (Littelfuse Inc. NANO²® 451 Series): The 045106.3MRSN meets electrical and mechanical substitution criteria with active product status. This part carries CSA, METI, and UR certifications. Note that DC voltage rating is not specified in the provided data for this part; verification against application requirements is necessary if DC operation is critical.

All substitute parts maintain ROHS3 compliance and unlimited moisture sensitivity level (MSL 1), ensuring compatibility with standard surface mount assembly processes.

Frequently Asked Questions (FAQ)

Q: Can the 0679L6300-05 be used as a direct replacement for the SSQ 6.3/5K? A: Yes. The 0679L6300-05 matches all core electrical parameters (6.3 A, 125 V AC/DC, fast blow) and mechanical specifications (2-SMD square end block, surface mount). The primary difference is product status: the 0679L6300-05 is active, whereas the SSQ 6.3/5K is obsolete.

Q: What is the difference between the Littelfuse 047606.3MR and 047606.3MRSN? A: Both parts are electrically and mechanically identical. The primary difference is packaging: 047606.3MR is supplied in Tape & Reel (TR), while 047606.3MRSN is also supplied in Tape & Reel (TR). Both are active products with identical electrical specifications.

Q: Why do the substitute parts have different melting I²t values? A: Melting I²t is a thermal characteristic that reflects the energy required to melt the fuse element. Variations in I²t among parts with identical current and voltage ratings result from differences in element design and material composition between manufacturers. All listed parts maintain fast blow response and meet the 6.3 A current rating requirement.

Q: Can I use the 045106.3MRSN if my application requires both AC and DC operation? A: The 045106.3MRSN data provided does not specify a DC voltage rating. If your application requires 125 V DC operation, use the 0679L6300-05, 047606.3MR, or 047606.3MRSN, which all explicitly rate 125 V DC.

Q: What is the significance of the different breaking capacities listed? A: Breaking capacity indicates the maximum fault current the fuse can safely interrupt without rupturing the case. The SSQ 6.3/5K and 045106.3MRSN are rated 50 A AC, while the Littelfuse 047606.3MR and 047606.3MRSN are rated 100 A AC. Higher breaking capacity provides additional safety margin in high fault current environments but does not affect normal circuit operation at rated current.

Q: Are all substitute parts RoHS compliant? A: Yes. All substitute parts listed are ROHS3 compliant and carry unlimited moisture sensitivity level (MSL 1), meeting standard environmental and assembly requirements.