SSQ 500 Equivalent & Substitute Parts

Part Overview

The Bel Fuse Inc. SSQ 500 is a 500 mA, 125 V AC/DC surface mount board mount fuse with fast blow response time, designed for 2-SMD square end block applications. This part is classified as obsolete, making equivalent and substitute parts necessary for ongoing design support and procurement. Substitute parts maintain the same electrical ratings, mechanical form factor compatibility, and functional performance while offering active product status and improved availability.

Substiute Parts

SSQ 500

Bel Fuse Inc.In Stock: 1059SSQ 500 Datasheet

Current PartRFQ

0679L0500-01

Bel Fuse Inc.In Stock: 33210679L0500-01 Datasheet

DirectRFQ

0451.500MRL

Littelfuse Inc.In Stock: 4611120451.500MRL Datasheet

SimilarRFQ

0451.500MRSN

Littelfuse Inc.In Stock: 8320451.500MRSN Datasheet

SimilarRFQ

0453.500MR

Littelfuse Inc.In Stock: 117570453.500MR Datasheet

SimilarRFQ

3404.0045.11

SCHURTER Inc.In Stock: 8783404.0045.11 Datasheet

SimilarRFQ

3404.0045.22

SCHURTER Inc.In Stock: 27463404.0045.22 Datasheet

SimilarRFQ

3404.0045.24

SCHURTER Inc.In Stock: 10823404.0045.24 Datasheet

SimilarRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution for the SSQ 500 is determined by strict equivalence across the following electrical and mechanical parameters:

• Current Rating: 500 mA (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)
• Operating Temperature Range: -55°C to 125°C (exact match required)
• RoHS Compliance: ROHS3 Compliant (exact match required)

Substitute parts are grouped into two categories based on package configuration:

Category 1: Square End Block (2-SMD) – Direct mechanical and electrical equivalents with identical footprint dimensions (0.240" L × 0.100" W × 0.100" H nominal).

Category 2: J-Lead (2-SMD) – Functionally equivalent with different lead configuration and slightly larger dimensions (0.291" L × 0.122" W × 0.102" H nominal). These parts require PCB layout verification for mechanical compatibility.

Parameter Comparison

Engineering Selection Recommendations

For Direct Footprint Replacement (Square End Block):

The Bel Fuse Inc. 0679L0500-01 is the primary direct substitute, offering identical electrical specifications and mechanical compatibility with the SSQ 500. This part maintains active product status and is available in Tape & Reel packaging with high inventory levels (3226 pcs).

The Littelfuse NANO²® 451 series (0451.500MRL, 0451.500MRSN) and NANO²® 453 series (0454.600MR) provide functionally equivalent alternatives with active status. These parts feature slightly different dimensional tolerances (0.106" width and height versus 0.100") but maintain the same 0.240" length and are compatible with standard 2-SMD square end block footprints. The 0454.600MR offers the highest inventory availability (11723 pcs) in Cut Tape & Digi-Reel packaging.

For Alternative Package Configuration (J-Lead):

The SCHURTER OMF 125 series (3404.0045.11, 3404.0045.22, 3404.0045.24) provides electrical equivalence with a different mechanical form factor. These parts feature J-Lead configuration with larger overall dimensions and higher breaking capacity (100A). Selection among these variants depends on packaging requirements: 3404.0045.11 for bulk, 3404.0045.22 and 3404.0045.24 for Tape & Reel. PCB layout verification is required due to dimensional differences.

Compliance and Certification:

All substitute parts maintain ROHS3 compliance and REACH unaffected status. Certification coverage varies: Bel Fuse 0679L0500-01 includes AEC-Q200 and cURus; Littelfuse parts include CSA and UL; SCHURTER parts include cURus certification. Design teams should verify certification alignment with application requirements.

Frequently Asked Questions (FAQ)

Q: Can the SSQ 500 be directly replaced with the 0679L0500-01?

A: Yes. The 0679L0500-01 is a direct electrical and mechanical equivalent with identical current rating (500 mA), voltage rating (125 V AC/DC), response time (Fast Blow), and mounting type (Surface Mount). The only difference is packaging format (Tape & Reel versus Cut Tape & Digi-Reel) and a minor height tolerance variation (0.110" versus 0.100"). Both are compatible with the same PCB footprint.

Q: What is the difference between the Littelfuse NANO²® 451 and NANO²® 453 series?

A: Both series meet the electrical specifications of the SSQ 500 (500 mA, 125 V AC/DC, Fast Blow). The primary difference is series designation and internal design. Both are functionally interchangeable for the SSQ 500 application. The 0454.600MR offers significantly higher inventory availability.

Q: Can SCHURTER OMF 125 parts be used as direct replacements?

A: SCHURTER OMF 125 parts (3404.0045.11, 3404.0045.22, 3404.0045.24) are electrically equivalent but use J-Lead configuration instead of square end block. Dimensions are larger (0.291" L × 0.122" W × 0.102" H versus 0.240" L × 0.100" W × 0.100" H). These parts require PCB layout verification and are suitable only if the design accommodates the different footprint.

Q: What packaging options are available for substitutes?

A: Substitute parts are available in multiple packaging formats: Tape & Reel (TR) for automated assembly, Cut Tape (CT) & Digi-Reel® for manual or semi-automated processes, and Bulk for high-volume applications. Selection depends on manufacturing process requirements and volume.

Q: Are all substitute parts ROHS3 compliant?

A: Yes. All listed substitute parts are ROHS3 compliant and REACH unaffected, matching the compliance status of the SSQ 500.

Q: Which substitute offers the best availability?

A: The Littelfuse 0454.600MR (NANO²® 453 series) offers the highest inventory level at 11,723 pcs, available in Cut Tape & Digi-Reel packaging. The Littelfuse 0451.500MRL provides 461,071 pcs in Tape & Reel format.