SSQ 4.6/5K Surface Mount Board Mount Fuse Equivalent & Substitute Parts

Part Overview

The SSQ 4.6/5K is a 4.6 A, 125 V AC/DC surface mount board mount fuse manufactured by Bel Fuse Inc. This part is classified as obsolete. Equivalent and substitute parts are necessary to maintain design continuity and ensure component availability for production and field replacement applications. Substitute parts must maintain electrical compatibility across current rating, voltage rating, response time, and mechanical form factor while meeting applicable regulatory approvals.

Substiute Parts

SSQ 3.5/5K

Bel Fuse Inc.In Stock: 1050SSQ 3.5/5K Datasheet

Current PartRFQ

0679L3500-05

Bel Fuse Inc.In Stock: 147410679L3500-05 Datasheet

DirectRFQ

047603.5MR

LittelfuseIn Stock: 1739047603.5MR Datasheet

DirectRFQ

047603.5MRSN

Littelfuse Inc.In Stock: 902047603.5MRSN Datasheet

DirectRFQ

045103.5MRSN

Littelfuse Inc.In Stock: 899045103.5MRSN Datasheet

SimilarRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution logic for the SSQ 4.6/5K is based on the following critical parameters:

Direct Equivalents maintain identical electrical specifications: 4.6 A current rating, 125 V AC and 125 V DC voltage ratings, fast blow response time, surface mount configuration, and 2-SMD square end block package. These parts are interchangeable without circuit modification.

Voltage-Enhanced Substitutes increase AC voltage rating to 250 V while maintaining 125 V DC rating and all other electrical characteristics. These parts provide higher voltage margin and are suitable for applications where the original 125 V AC specification is adequate but higher voltage capability is beneficial.

Similar Parts share the same current rating, response time, and mounting configuration but may differ in voltage rating or other secondary parameters. These require circuit-level evaluation for compatibility.

Parameter Comparison

Engineering Selection Recommendations

For Direct Replacement (Obsolete to Active): The 0679L3500-05 from Bel Fuse Inc. is the primary direct equivalent. It maintains identical electrical ratings (4.6 A, 125 V AC/DC, fast blow) and package configuration. This part is active in production with AEC-Q200 and cURus approvals. The melting I²t value of 2.2 is lower than the original 3.9, indicating faster thermal response. DC cold resistance is slightly lower at 0.022 Ω versus 0.024 Ω. Both differences are within acceptable engineering tolerance for fuse substitution.

For Voltage-Enhanced Applications: The 047604.6MR and 047604.6MRSN from Littelfuse (NANO²® 476 series) provide 250 V AC rating while maintaining 125 V DC and 4.6 A current rating. These parts are suitable for circuits where 125 V AC is the design specification but higher voltage margin is desired. Breaking capacity increases to 100A AC. Both parts carry cURus approval. The 047604.6MRSN variant is supplied in Tape & Reel packaging.

For AC-Only Applications: The 045104.6MRSN from Littelfuse (NANO²® 451 series) maintains 4.6 A and 125 V AC rating with fast blow response. This part is suitable only for AC circuits or where DC voltage specification is not required. It carries CSA, METI, and UR approvals.

Compliance Considerations: All substitute parts are ROHS3 compliant, REACH unaffected, and classified as EAR99. All maintain MSL 1 (unlimited moisture sensitivity level) and operating temperature range of -55°C to 125°C.

Frequently Asked Questions (FAQ)

Q: Can the 0679L3500-05 directly replace the SSQ 4.6/5K without circuit modification? A: Yes. The 0679L3500-05 maintains identical current rating (4.6 A), voltage ratings (125 V AC/DC), response time (fast blow), and package configuration (2-SMD square end block). Both parts are ROHS3 compliant with MSL 1 rating.

Q: What is the difference between the Littelfuse 047604.6MR and 047604.6MRSN? A: Both parts are electrically identical with 4.6 A, 250 V AC, 125 V DC ratings and fast blow response. The primary difference is packaging: 047604.6MR and 047604.6MRSN are both supplied in Tape & Reel format. Verify packaging requirements for your assembly process.

Q: Can I use a 250 V AC rated fuse in a 125 V AC circuit? A: Yes. A fuse rated for higher voltage can be used in lower voltage applications. The 047604.6MR and 047604.6MRSN (250 V AC rated) are suitable for 125 V AC circuits. Verify that all other electrical parameters (current rating, response time, DC voltage if applicable) match circuit requirements.

Q: Is the 045104.6MRSN suitable as a replacement for the SSQ 4.6/5K? A: The 045104.6MRSN is suitable only if your circuit operates on AC voltage exclusively. It maintains 4.6 A and 125 V AC ratings but does not specify DC voltage rating. If your circuit requires DC voltage protection, use the 0679L3500-05 or the Littelfuse 250 V AC rated alternatives.

Q: What does the melting I²t value indicate? A: Melting I²t is a thermal energy parameter that characterizes fuse response speed. Lower values indicate faster thermal response. The 0679L3500-05 (I²t = 2.2) responds faster than the original SSQ 4.6/5K (I²t = 3.9). This difference is acceptable for most applications but should be verified if precise thermal coordination is required in your circuit protection scheme.

Q: Are all substitute parts RoHS compliant? A: Yes. All parts listed are ROHS3 compliant and REACH unaffected, meeting current environmental and regulatory requirements.