SST 1.5 Equivalent & Substitute Parts

Part Overview

The SST 1.5 is a 1.5 A 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. Identifying equivalent and substitute parts is necessary to maintain design continuity, ensure supply chain availability, and support ongoing production requirements for applications requiring 1.5 A fuse protection in surface mount configurations.

Key Parameters

Parameter	Value
Current Rating	1.5 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 1.5 are grouped into two categories based on allowed electrical and mechanical parameters:

Direct Substitutes (0680L Series - Bel Fuse Inc.) Parts 0680L1500-01, 0680L1500-05, 0680L1500-11, 0680L1500-15, and 0680L1500-21 maintain identical electrical specifications: 1.5 A current rating, 125 V AC/DC voltage rating, slow blow response time, and identical physical dimensions (0.240" L x 0.100" W x 0.100" H). These parts differ only in packaging configuration (Tape & Reel vs. Cut Tape) and internal lead frame design, which do not affect functional performance in the circuit. All are active product status with enhanced breaking capacity (50A AC, 100A DC) and improved melting I²t characteristics (3.3 vs. 3.0).

Parametric Equivalents (0680H Series - Bel Fuse Inc.) Parts 0680H1500-01 and 0680H1500-05 share identical current rating (1.5 A), voltage rating (125 V AC/DC), response time (slow blow), and physical dimensions. These parts feature higher breaking capacity (100A AC, 500A DC) and lower melting I²t (1.7), indicating faster response characteristics. Selection requires verification that the application circuit can tolerate faster fuse response.

Cross-Manufacturer Alternatives (Littelfuse Inc.) Parts 044901.5MR and 045201.5MRL from Littelfuse Inc. maintain the required 1.5 A current rating, 125 V AC/DC voltage rating, slow blow response, and surface mount configuration. Physical dimensions are nominally equivalent (0.240" L x 0.106" W x 0.106" H vs. 0.240" L x 0.100" W x 0.100" H), representing minor dimensional variation within standard PCB footprint tolerance. These parts are from different fuse series (NANO²® 449 and NANO²® 452) with different melting I²t values (4.7 and 3.65 respectively).

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
SST 1.5	Bel Fuse Inc.	1.5	125	125	Slow Blow	50	—	3.0	0.081	Obsolete
0680L1500-01	Bel Fuse Inc.	1.5	125	125	Slow Blow	50	100	3.3	0.095	Active
0680L1500-05	Bel Fuse Inc.	1.5	125	125	Slow Blow	50	100	3.3	0.095	Active
0680L1500-11	Bel Fuse Inc.	1.5	125	125	Slow Blow	50	100	3.3	0.095	Active
0680L1500-15	Bel Fuse Inc.	1.5	125	125	Slow Blow	50	100	3.3	0.095	Active
0680L1500-21	Bel Fuse Inc.	1.5	125	125	Slow Blow	50	100	3.3	0.095	Active
0680L1500-25	Bel Fuse Inc.	1.5	125	125	Slow Blow	50	100	3.3	0.095	Active
0680H1500-01	Bel Fuse Inc.	1.5	125	125	Slow Blow	100	500	1.7	0.175	Active
0680H1500-05	Bel Fuse Inc.	1.5	125	125	Slow Blow	100	500	1.7	0.175	Active
044901.5MR	Littelfuse Inc.	1.5	125	125	Slow Blow	50	—	4.7	0.1186	Active
045201.5MRL	Littelfuse Inc.	1.5	125	125	Slow Blow	50	—	3.65	0.093	Active

Engineering Selection Recommendations

Primary Recommendation: 0680L Series (0680L1500-01, 0680L1500-05, 0680L1500-11, 0680L1500-15, 0680L1500-21, 0680L1500-25)

The 0680L series represents the direct functional replacement for the obsolete SST 1.5. All variants maintain identical electrical ratings and physical dimensions while offering active product status with full manufacturing support. These parts carry AEC-Q200 and CE certifications matching the original specification. The 0680L series is available in high inventory quantities (700–42,143 pieces), ensuring supply chain continuity. Selection among 0680L variants depends on packaging requirements: Tape & Reel (TR) for automated assembly or Cut Tape (CT) for manual placement.

Secondary Recommendation: 0680H Series (0680H1500-01, 0680H1500-05)

The 0680H series provides parametric equivalence with enhanced breaking capacity and faster response characteristics. These parts are suitable for applications where higher fault current withstand capability (100A AC, 500A DC vs. 50A AC, 100A DC) is beneficial. The lower melting I²t (1.7 vs. 3.3) indicates faster thermal response, which may alter circuit protection timing. Selection requires confirmation that the application circuit design accommodates faster fuse response without introducing nuisance trips. Certification is limited to cURus, which may not satisfy all regional compliance requirements.

Tertiary Recommendation: Littelfuse NANO²® Series (044901.5MR, 045201.5MRL)

Cross-manufacturer alternatives from Littelfuse Inc. maintain the required 1.5 A current rating and 125 V AC/DC voltage rating. Physical dimensions show minor variation (0.106" width and height vs. 0.100"), which remains within standard PCB footprint tolerance for 2-SMD square end block packages. The 045201.5MRL variant offers melting I²t (3.65) closest to the original SST 1.5 specification (3.0). These parts carry PSE and CSA certifications. Selection of Littelfuse alternatives requires verification of PCB footprint compatibility and confirmation that regional compliance requirements accept the specified certifications.

Frequently Asked Questions (FAQ)

Q: Can the 0680L series directly replace the SST 1.5 without PCB modification?

A: Yes. The 0680L series maintains identical physical dimensions (0.240" L x 0.100" W x 0.100" H) and electrical ratings (1.5 A, 125 V AC/DC, slow blow response). PCB footprints designed for SST 1.5 accommodate 0680L variants without modification. Packaging configuration (Tape & Reel vs. Cut Tape) affects assembly process but not electrical or mechanical compatibility.

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

A: Both series share identical current rating (1.5 A), voltage rating (125 V AC/DC), and physical dimensions. The 0680H series features higher breaking capacity (100A AC, 500A DC vs. 50A AC, 100A DC) and lower melting I²t (1.7 vs. 3.3), resulting in faster thermal response. Applications requiring faster fault detection may benefit from 0680H selection, but circuit design must accommodate the altered response timing to prevent nuisance trips.

Q: Are Littelfuse NANO²® fuses compatible with SST 1.5 footprints?

A: Littelfuse NANO²® parts maintain the required 1.5 A current rating and 125 V AC/DC voltage rating. Physical dimensions show minor variation: 0.240" L x 0.106" W x 0.106" H versus 0.240" L x 0.100" W x 0.100" H. This 0.006" dimensional difference in width and height remains within standard PCB footprint tolerance for 2-SMD square end block packages. Verification with PCB design documentation is recommended to confirm footprint acceptance.

Q: Which substitute part offers the closest electrical match to the original SST 1.5?

A: The 0680L series provides the closest electrical match with identical current rating, voltage rating, response time, and physical dimensions. Melting I²t increases slightly from 3.0 to 3.3, representing a 10% change within normal manufacturing tolerance. The 045201.5MRL from Littelfuse offers melting I²t of 3.65, which is closer to the original specification than other alternatives.

Q: What certifications should I verify when selecting a substitute?

A: The original SST 1.5 carries AEC-Q200, CE, CSA, and cULus certifications. The 0680L series maintains AEC-Q200 and CE certifications. The 0680H series carries only cURus certification. Littelfuse alternatives carry PSE, CSA, and UR (045201.5MRL) or cULus and PSE (044901.5MR) certifications. Verify that selected substitute certifications satisfy regional compliance requirements for your application.

Q: Does packaging type (Tape & Reel vs. Cut Tape) affect electrical performance?

A: No. Packaging type affects assembly process and handling but does not alter electrical performance, current rating, voltage rating, or response characteristics. Selection between Tape & Reel and Cut Tape depends on manufacturing process requirements and assembly equipment compatibility.

Request Quote (Ships tomorrow)

Part Number

Quantity

Company

Contact Name

E-mail

Message