SST 750/5K Equivalent & Substitute Parts Reference

Part Overview

The SST 750/5K is a 750 mA surface mount board mount fuse rated for 125 V AC/DC operation manufactured by Bel Fuse Inc. This component is classified as obsolete product status. Direct substitutes and parametric equivalents are available from both Bel Fuse and Littelfuse to maintain design continuity and ensure supply chain reliability for applications requiring 750 mA fuse protection in SMD configurations.

Key Parameters

Parameter	Value
Current Rating	750 mA
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 Range	-55°C ~ 125°C
RoHS Status	ROHS3 Compliant
Moisture Sensitivity Level	1 (Unlimited)

Substitute Part Grouping Explanation

Substitution eligibility is determined by strict equivalence across the following parameters: current rating (750 mA), voltage ratings (125 V AC/DC), response time (Slow Blow), mounting type (Surface Mount), package configuration (2-SMD, Square End Block), and physical dimensions (0.240" L x 0.100" W x 0.100" H). Parts are grouped into two categories:

Direct Manufacturer Substitutes (Bel Fuse 0680L Series): Parts 0680L0750-11, 0680L0750-15, 0680L0750-21, and 0680L0750-25 meet all electrical and mechanical parameters. These are active product status alternatives with identical current, voltage, and package specifications. Differences in breaking capacity and melting I²t do not affect substitution eligibility for the specified application parameters.

Parametric Equivalents (Bel Fuse 0680H Series and 0680L Extended Range): Parts 0680H0750-01, 0680H0750-05, 0680L0750-01, and 0680L0750-05 maintain identical electrical ratings and physical dimensions. The 0680H series exhibits higher breaking capacity (100A AC, 500A DC versus 50A AC) and lower melting I²t (0.28 versus 0.66), representing enhanced performance characteristics within the same form factor.

Cross-Manufacturer Equivalent (Littelfuse 0449.750MR): The Littelfuse NANO²® 449 series part 0449.750MR provides parametric equivalence with identical current, voltage, and response time ratings. Physical dimensions vary slightly (0.106" W x 0.106" H versus 0.100" W x 0.100" H), and melting I²t differs (0.847 versus 0.66).

Parameter Comparison

Part Number	Manufacturer	Product Status	Current Rating (mA)	Voltage AC/DC (V)	Response Time	Breaking Capacity AC / DC	Melting I²t	DC Cold Resistance (Ω)	Packaging
SST 750/5K	Bel Fuse Inc.	Obsolete	750	125 / 125	Slow Blow	50A / —	0.66	0.25	Cut Tape & Digi-Reel®
0680L0750-11	Bel Fuse	Active	750	125 / 125	Slow Blow	50A / 100A	0.62	0.33	Tape & Reel (TR)
0680L0750-15	Bel Fuse	Active	750	125 / 125	Slow Blow	50A / 100A	0.62	0.33	Tape & Reel (TR)
0680L0750-21	Bel Fuse	Active	750	125 / 125	Slow Blow	50A / 100A	0.62	0.33	Tape & Reel (TR)
0680L0750-25	Bel Fuse	Active	750	125 / 125	Slow Blow	50A / 100A	0.62	0.33	Tape & Reel (TR)
0680H0750-01	Bel Fuse Inc.	Active	750	125 / 125	Slow Blow	100A / 500A	0.28	0.53	Tape & Reel (TR)
0680H0750-05	Bel Fuse Inc.	Active	750	125 / 125	Slow Blow	100A / 500A	0.28	0.53	Tape & Reel (TR)
0680L0750-01	Bel Fuse Inc.	Active	750	125 / 125	Slow Blow	50A / 100A	0.62	0.33	Tape & Reel (TR)
0680L0750-05	Bel Fuse Inc.	Active	750	125 / 125	Slow Blow	50A / 100A	0.62	0.33	Tape & Reel (TR)
SST 750	Bel Fuse Inc.	Obsolete	750	125 / 125	Slow Blow	50A / —	0.66	0.25	Cut Tape & Digi-Reel®
0449.750MR	Littelfuse Inc.	Active	750	125 / 125	Slow Blow	50A / —	0.847	0.408	Tape & Reel (TR)

Engineering Selection Recommendations

Primary Substitutes (Bel Fuse 0680L Series): Parts 0680L0750-11, 0680L0750-15, 0680L0750-21, and 0680L0750-25 are active product status alternatives with full compliance to AEC-Q200, CE, and cURus certifications. These parts are recommended for direct replacement where Tape & Reel packaging is acceptable. All four variants maintain identical electrical specifications and are interchangeable from an application standpoint.

Enhanced Performance Alternatives (Bel Fuse 0680H Series): Parts 0680H0750-01 and 0680H0750-05 provide higher breaking capacity ratings (100A AC, 500A DC) while maintaining the same current and voltage ratings. These are active product status components with cURus certification. Selection of the 0680H series is appropriate where enhanced fault current handling is required within the same physical footprint.

Extended Parametric Equivalents (Bel Fuse 0680L Extended Range): Parts 0680L0750-01 and 0680L0750-05 are active product status alternatives with AEC-Q200, CE, and cURus certifications. These parts provide identical electrical and mechanical compatibility with the SST 750/5K.

Cross-Manufacturer Option (Littelfuse 0449.750MR): The Littelfuse NANO²® 449 series part 0449.750MR is an active product status alternative with cULus certification. Physical dimensions vary slightly in width and height (0.106" versus 0.100"), and melting I²t is higher (0.847 versus 0.66). This part is suitable where Littelfuse supply chain preference or specific certification requirements apply.

Frequently Asked Questions (FAQ)

Q: Can I use 0680L0750-21 as a direct replacement for SST 750/5K?

A: Yes. The 0680L0750-21 meets all electrical parameters: 750 mA current rating, 125 V AC/DC voltage rating, Slow Blow response time, and identical 2-SMD Square End Block package dimensions (0.240" L x 0.100" W x 0.100" H). The primary difference is packaging format (Tape & Reel versus Cut Tape & Digi-Reel®) and active product status versus obsolete status.

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

A: Both series maintain identical current (750 mA), voltage (125 V AC/DC), and physical dimensions. The 0680H series provides higher breaking capacity (100A AC, 500A DC versus 50A AC, 100A DC) and lower melting I²t (0.28 versus 0.62). Selection depends on fault current requirements in the application circuit.

Q: Is the Littelfuse 0449.750MR compatible with the SST 750/5K?

A: The 0449.750MR provides parametric equivalence in current rating (750 mA), voltage rating (125 V AC/DC), and response time (Slow Blow). Physical dimensions vary slightly (0.106" W x 0.106" H versus 0.100" W x 0.100" H), and melting I²t differs (0.847 versus 0.66). PCB layout verification is required to confirm mechanical fit.

Q: Why are there multiple part numbers within the 0680L series (0680L0750-11, -15, -21, -25)?

A: These part numbers represent different packaging reel configurations or manufacturing date codes within the same electrical and mechanical specification. All four variants are electrically and mechanically identical and are interchangeable for application purposes.

Q: What certifications apply to substitute parts?

A: The Bel Fuse 0680L series (0680L0750-11, -15, -21, -25, -01, -05) carries AEC-Q200, CE, and cURus certifications. The Bel Fuse 0680H series (0680H0750-01, -05) carries cURus certification. The Littelfuse 0449.750MR carries cULus certification. Verify certification requirements for your specific application before selection.

Q: Can I substitute SST 750 (obsolete) with an active product?

A: Yes. The 0680L0750-01, 0680L0750-05, 0680L0750-11, 0680L0750-15, 0680L0750-21, and 0680L0750-25 are all active product status alternatives with identical electrical specifications. These parts eliminate supply chain risk associated with obsolete product sourcing.

Request Quote (Ships tomorrow)

Part Number

Quantity

Company

Contact Name

E-mail

Message