SSQ 8/5K Equivalent & Substitute Parts

Part Overview

The SSQ 8/5K is an 8 A, 125 V AC / 86 V DC surface mount board mount fuse manufactured by Bel Fuse Inc. This component is classified as obsolete, making identification of suitable substitute parts essential for ongoing design support and production continuity. The fast-blow response characteristic and 2-SMD square end block package define its application scope in circuit protection applications requiring precise current limiting at specified voltage ratings.

Key Parameters

Parameter	Value
Current Rating	8 A
Voltage Rating - AC	125 V
Voltage Rating - DC	86 V
Response Time	Fast Blow
Mounting Type	Surface Mount
Package / Case	2-SMD, Square End Block
Operating Temperature Range	-55°C ~ 125°C
Size / Dimension	0.240" L x 0.100" W x 0.100" H (6.10mm x 2.54mm x 2.54mm)
Breaking Capacity @ Rated Voltage	50A AC, 10kA DC
Melting I²t	26
DC Cold Resistance	0.008 Ohms
RoHS Status	ROHS3 Compliant
Approval Agency	CE, cULus

Substitute Part Grouping Explanation

Substitution eligibility for the SSQ 8/5K is determined by the following critical parameters:

Current Rating: Must be 8 A
Voltage Rating - AC: Must be 125 V or higher
Voltage Rating - DC: Must be 86 V or higher
Response Time: Must be Fast Blow
Mounting Type: Must be Surface Mount
Package / Case: Must be 2-SMD, Square End Block
Operating Temperature Range: Must encompass -55°C ~ 125°C
RoHS Status: Must be ROHS3 Compliant

The substitute part 0679L8000-05 meets all substitution criteria. It maintains identical current rating, AC voltage rating, response time, mounting type, and package configuration. The DC voltage rating of 125 V exceeds the minimum requirement of 86 V, providing enhanced voltage margin. Both parts are ROHS3 compliant and operate across the same temperature range.

Parameter Comparison

Parameter	SSQ 8/5K	0679L8000-05	Compatibility
Current Rating (Amps)	8 A	8 A	Identical
Voltage Rating - AC	125 V	125 V	Identical
Voltage Rating - DC	86 V	125 V	Substitute exceeds requirement
Response Time	Fast Blow	Fast Blow	Identical
Mounting Type	Surface Mount	Surface Mount	Identical
Package / Case	2-SMD, Square End Block	2-SMD, Square End Block	Identical
Operating Temperature Range	-55°C ~ 125°C	-55°C ~ 125°C	Identical
Size / Dimension	0.240" L x 0.100" W x 0.100" H (6.10mm x 2.54mm x 2.54mm)	0.240" L x 0.100" W x 0.110" H (6.10mm x 2.54mm x 2.79mm)	Height variance: 0.010" (0.25mm)
Breaking Capacity @ Rated Voltage	50A AC, 10kA DC	50A AC, 300A DC	AC identical; DC capacity differs
Melting I²t	26	14.1	Substitute has lower thermal energy rating
DC Cold Resistance	0.008 Ohms	0.0089 Ohms	Negligible difference
RoHS Status	ROHS3 Compliant	ROHS3 Compliant	Identical
Approval Agency	CE, cULus	AEC-Q200, cURus	Different certifications
Product Status	Obsolete	Active	Substitute is in active production

Engineering Selection Recommendations

The 0679L8000-05 is a direct functional substitute for the obsolete SSQ 8/5K based on matching current rating, AC voltage rating, response time, mounting type, and package configuration. The substitute part is in active production status, ensuring long-term availability and supply chain continuity.

The substitute part carries AEC-Q200 automotive qualification in addition to cURus certification, whereas the original part carries CE and cULus certifications. Selection between these parts should be based on application-specific compliance requirements. The substitute's higher DC voltage rating (125 V versus 86 V) provides additional voltage margin without compromising circuit protection function.

Physical dimensions differ slightly in height (0.110" versus 0.100"), a variance of 0.010" (0.25mm). PCB layout and assembly clearance must be evaluated to confirm accommodation of this dimensional change. The substitute part is available in Tape & Reel packaging, supporting automated assembly processes.

Frequently Asked Questions (FAQ)

Q: Can the 0679L8000-05 directly replace the SSQ 8/5K in existing designs?

A: The 0679L8000-05 meets all critical electrical parameters for substitution: identical 8 A current rating, 125 V AC voltage rating, and fast-blow response time. Physical dimensions differ by 0.010" in height. PCB layout verification is required to confirm clearance compatibility before implementation.

Q: What is the significance of the different DC voltage ratings?

A: The SSQ 8/5K is rated for 86 V DC, while the 0679L8000-05 is rated for 125 V DC. The substitute part's higher rating provides enhanced voltage margin and is suitable for applications requiring the original 86 V DC specification. The substitute will not compromise protection in circuits designed for the lower voltage rating.

Q: Why do the two parts have different approval certifications?

A: The SSQ 8/5K carries CE and cULus certifications. The 0679L8000-05 carries AEC-Q200 and cURus certifications. AEC-Q200 is an automotive-grade qualification. Selection should be based on application requirements and regional compliance mandates.

Q: What does the difference in Melting I²t values indicate?

A: The SSQ 8/5K has a Melting I²t of 26, while the 0679L8000-05 has a Melting I²t of 14.1. This parameter describes thermal energy required to melt the fuse element. The substitute part will respond faster to thermal stress. Both parts maintain the same 8 A current rating and fast-blow response classification.

Q: Is the packaging difference significant?

A: The SSQ 8/5K is supplied in standard packaging, while the 0679L8000-05 is available in Tape & Reel (TR) format. Tape & Reel packaging is optimized for automated assembly processes and high-volume production. This difference does not affect electrical or mechanical compatibility.

Q: Are both parts RoHS compliant?

A: Both the SSQ 8/5K and 0679L8000-05 are ROHS3 compliant, meeting current environmental and hazardous substance restrictions for electronic components.

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