SST 7 Equivalent & Substitute Parts

Part Overview

The SST 7 is a 7 A 125 V AC/DC surface mount board mount fuse manufactured by Bel Fuse Inc. with slow blow response characteristics. This component is classified as obsolete, necessitating identification of active equivalent and substitute parts for ongoing design support and procurement continuity. The SST series has been superseded by active product lines offering improved electrical performance and broader approval certifications while maintaining mechanical and electrical compatibility.

Key Parameters

Parameter	Value
Current Rating	7 A
Voltage Rating AC	125 V
Voltage Rating DC	125 V
Response Time	Slow Blow
Mounting Type	Surface Mount
Package / Case	2-SMD, Square End Block
Size / Dimension	0.240" L x 0.100" W x 0.100" H (6.10mm x 2.54mm x 2.54mm)
Operating Temperature	-55°C ~ 125°C
RoHS Status	ROHS3 Compliant
Moisture Sensitivity Level	1 (Unlimited)

Substitute Part Grouping Explanation

Substitute parts for the SST 7 are classified into two categories based on electrical and mechanical compatibility:

Direct Manufacturer Substitutes (0680L Series): Parts 0680L7000-01, 0680L7000-05, 0680L7000-11, 0680L7000-15, 0680L7000-21, and 0680L7000-25 are direct substitutes manufactured by Bel Fuse Inc. These parts maintain identical current rating (7 A), voltage ratings (125 V AC/DC), response time (Slow Blow), package configuration (2-SMD, Square End Block), and physical dimensions. All are active products with ROHS3 compliance and unlimited moisture sensitivity rating. The primary differences are breaking capacity specifications and melting I²t values, which do not affect basic circuit protection functionality at rated parameters.

Parametric Equivalents (0680H Series): Parts 0680H7000-01 and 0680H7000-05 are parametric equivalents from the 0680H series. These maintain the same current rating, voltage ratings, response time, package type, and physical dimensions as the SST 7. The 0680H series offers enhanced breaking capacity (100 A AC / 500 A DC versus 50 A AC) and lower melting I²t (48 versus 80), providing superior fault current handling while preserving compatibility with the original circuit design parameters.

Similar Part (0452007.MRSN): The Littelfuse 0452007.MRSN is a similar 7 A slow blow surface mount fuse with reduced voltage rating (72 V AC/DC versus 125 V AC/DC). This part is suitable only for applications with lower voltage requirements and should not be used as a direct replacement in 125 V circuits.

Parameter Comparison

Part Number	Manufacturer	Current Rating (A)	Voltage AC (V)	Voltage DC (V)	Response Time	Breaking Capacity AC (A)	Breaking Capacity DC (A)	Melting I²t	DC Cold Resistance (Ω)	Product Status	Packaging
SST 7	Bel Fuse Inc.	7	125	125	Slow Blow	50	—	80	0.011	Obsolete	Cut Tape (CT) & Digi-Reel®
0680L7000-01	Bel Fuse Inc.	7	125	125	Slow Blow	50	100	68	0.012	Active	Tape & Reel (TR)
0680L7000-05	Bel Fuse Inc.	7	125	125	Slow Blow	50	100	68	0.012	Active	Tape & Reel (TR)
0680L7000-11	Bel Fuse Inc.	7	125	125	Slow Blow	50	100	68	0.012	Active	Tape & Reel (TR)
0680L7000-15	Bel Fuse Inc.	7	125	125	Slow Blow	50	100	68	0.012	Active	Tape & Reel (TR)
0680L7000-21	Bel Fuse Inc.	7	125	125	Slow Blow	50	100	68	0.012	Active	Tape & Reel (TR)
0680L7000-25	Bel Fuse Inc.	7	125	125	Slow Blow	50	100	68	0.012	Active	Tape & Reel (TR)
0680H7000-01	Bel Fuse Inc.	7	125	125	Slow Blow	100	500	48	0.015	Active	Tape & Reel (TR)
0680H7000-05	Bel Fuse Inc.	7	125	125	Slow Blow	100	500	48	0.015	Active	Tape & Reel (TR)
0452007.MRSN	Littelfuse Inc.	7	72	72	Slow Blow	50	—	123.83	0.0105	Active	Tape & Reel (TR)

Engineering Selection Recommendations

For applications requiring direct replacement of the obsolete SST 7, the 0680L series (0680L7000-01, 0680L7000-05, 0680L7000-11, 0680L7000-15, 0680L7000-21, 0680L7000-25) provides full electrical and mechanical compatibility. All 0680L variants are active products with ROHS3 compliance and carry AEC-Q200 and CE certifications matching or exceeding the original SST 7 approvals. These parts are available in Tape & Reel packaging suitable for automated assembly.

The 0680H series (0680H7000-01, 0680H7000-05) offers enhanced performance characteristics with superior breaking capacity and lower melting I²t, making them suitable for applications requiring higher fault current withstand capability. These parts maintain full voltage and current rating compatibility with the SST 7 and are appropriate for designs where improved transient protection is beneficial.

The Littelfuse 0452007.MRSN is suitable only for circuits operating at 72 V AC/DC or lower and should not be selected as a replacement for 125 V applications.

Frequently Asked Questions (FAQ)

Q: Can the 0680L series parts be used interchangeably with the SST 7?

A: Yes. The 0680L series maintains identical current rating (7 A), voltage ratings (125 V AC/DC), response time (Slow Blow), package configuration (2-SMD, Square End Block), and physical dimensions (0.240" L x 0.100" W x 0.100" H). All variants are active products with current certifications.

Q: What is the difference between the 0680L and 0680H series?

A: Both series maintain the same current and voltage ratings. The 0680H series provides enhanced breaking capacity (100 A AC / 500 A DC versus 50 A AC) and lower melting I²t (48 versus 68), offering superior fault current handling. Selection depends on circuit fault current requirements.

Q: Why are there multiple part numbers within the 0680L series?

A: The 0680L7000-01, 0680L7000-05, 0680L7000-11, 0680L7000-15, 0680L7000-21, and 0680L7000-25 variants represent different manufacturing dates or tape configurations within the same electrical specification. All are electrically and mechanically identical for circuit design purposes.

Q: Is the 0452007.MRSN a suitable replacement for the SST 7?

A: No. The 0452007.MRSN has a reduced voltage rating of 72 V AC/DC compared to the SST 7's 125 V AC/DC rating. It is suitable only for lower voltage applications and should not be used in 125 V circuits.

Q: What packaging formats are available for substitute parts?

A: The 0680L and 0680H series are supplied in Tape & Reel (TR) format for automated assembly. The original SST 7 was available in Cut Tape (CT) & Digi-Reel® format. Tape & Reel packaging is standard for current production and is compatible with standard pick-and-place equipment.

Q: Are all substitute parts ROHS3 compliant?

A: Yes. All listed substitute parts (0680L series, 0680H series, and 0452007.MRSN) are ROHS3 compliant with unlimited moisture sensitivity rating (MSL 1).

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