SSQ 1.5 Equivalent & Substitute Parts

Part Overview

The SSQ 1.5 is a 1.5 A 125 V AC/DC surface mount board mount fuse manufactured by Bel Fuse Inc. in a 2-SMD, Square End Block package. This part is classified as Obsolete, making equivalent and substitute parts necessary for ongoing design support and procurement. The SSQ 1.5 series provides fast-blow protection with a breaking capacity of 50 A AC and 300 A DC, suitable for general-purpose circuit protection applications requiring compact surface mount form factors.

Key Parameters

Parameter	Value
Current Rating	1.5 A
Voltage Rating (AC)	125 V
Voltage Rating (DC)	125 V
Response Time	Fast Blow
Mounting Type	Surface Mount
Fuse Type	Board Mount (Cartridge Style Excluded)
Breaking Capacity (AC)	50 A
Breaking Capacity (DC)	300 A
Operating Temperature Range	-55°C to 125°C
RoHS Status	ROHS3 Compliant
Moisture Sensitivity Level	1 (Unlimited)

Substitute Part Grouping Explanation

Substitute parts for the SSQ 1.5 are classified into three categories based on electrical and mechanical compatibility:

Direct Manufacturer Equivalents (Same Manufacturer - Bel Fuse Inc.):

SSQ 1.5/5K: Parametric equivalent with identical electrical ratings, voltage specifications, and breaking capacity. Both parts are Obsolete status within the SSQ series.
0679L1500-01: Active production equivalent from Bel Fuse Inc. with matching current and voltage ratings. Differs in Melting I²t (0.29 vs. 0.57) and height dimension (2.79 mm vs. 2.54 mm). Packaging is Tape & Reel (TR) versus Cut Tape (CT) & Digi-Reel® for the main part.

Direct Cross-Manufacturer Equivalents (Littelfuse Inc. - NANO²® Series):

045101.5MRL: Active production part with identical current (1.5 A) and voltage ratings (125 V AC/DC). Melting I²t is 0.853 (higher than SSQ 1.5 at 0.57). Dimensions vary slightly (2.69 mm height vs. 2.54 mm). Package/Case is 2-SMD, Square End Block. Breaking capacity is 50 A AC only (no DC specification provided).
045101.5MRSN: Active production part with matching 1.5 A current rating and 125 V AC rating. Voltage Rating DC is not specified in the data. Melting I²t is 0.853. Dimensions are 2.69 mm height. Packaging is Tape & Reel (TR).

Similar Functional Equivalents (Littelfuse Inc. - NANO²® Series):

045301.5MR: Active production part with identical 1.5 A and 125 V AC/DC ratings. Melting I²t is 0.853. Dimensions are 2.69 mm height. NANO²® 453 series variant.
047601.6MR: Similar form factor but with higher current rating (1.6 A) and higher AC voltage rating (250 V AC vs. 125 V AC). DC voltage remains 125 V. Melting I²t is 0.62. Breaking capacity is 100 A AC and 300 A DC. This part is suitable only for applications requiring higher voltage or current margins.

Similar Functional Equivalents (SCHURTER Inc. - OMF 125 Series):

3404.0047.22: Active production part with matching 1.5 A and 125 V AC/DC ratings. Package/Case is 2-SMD, J-Lead (different lead style from Square End Block). Melting I²t is 0.24 (significantly lower). Breaking capacity is 100 A. Dimensions are 7.40 mm L × 3.10 mm W × 2.60 mm H.
3404.0047.11: Identical electrical and mechanical specifications to 3404.0047.22, with Bulk packaging instead of Tape & Reel (TR).

Substitution Logic: Electrical compatibility is determined by matching current rating (1.5 A), AC voltage rating (125 V), and DC voltage rating (125 V). Mechanical compatibility requires Surface Mount mounting type and 2-SMD package configuration. Parts with identical Melting I²t values provide direct thermal protection equivalence. Variations in Melting I²t, breaking capacity, and physical dimensions must be evaluated against specific application requirements.

Parameter Comparison

Part Number	Manufacturer	Current (A)	Voltage AC (V)	Voltage DC (V)	Response Time	Melting I²t	Breaking Capacity AC (A)	Breaking Capacity DC (A)	Package/Case	Status
SSQ 1.5	Bel Fuse Inc.	1.5	125	125	Fast Blow	0.57	50	300	2-SMD, Square End Block	Obsolete
SSQ 1.5/5K	Bel Fuse Inc.	1.5	125	125	Fast Blow	0.57	50	300	2-SMD, Square End Block	Obsolete
0679L1500-01	Bel Fuse Inc.	1.5	125	125	Fast Blow	0.29	50	300	2-SMD, Square End Block	Active
045101.5MRL	Littelfuse Inc.	1.5	125	125	Fast Blow	0.853	50	—	2-SMD, Square End Block	Active
045101.5MRSN	Littelfuse Inc.	1.5	125	—	Fast Blow	0.853	50	—	2-SMD, Square End Block	Active
045301.5MR	Littelfuse Inc.	1.5	125	125	Fast Blow	0.853	50	—	2-SMD, Square End Block	Active
047601.6MR	Littelfuse Inc.	1.6	250	125	Fast Blow	0.62	100	300	2-SMD, Square End Block	Active
3404.0047.22	SCHURTER Inc.	1.5	125	125	Fast Blow	0.24	100	—	2-SMD, J-Lead	Active
3404.0047.11	SCHURTER Inc.	1.5	125	125	Fast Blow	0.24	100	—	2-SMD, J-Lead	Active

Engineering Selection Recommendations

Primary Recommendation - Direct Equivalent: 0679L1500-01 (Bel Fuse Inc.) is the preferred substitute. It maintains the same manufacturer lineage, identical electrical ratings (1.5 A, 125 V AC/DC), and Active product status. The lower Melting I²t (0.29 vs. 0.57) provides faster thermal response, which is acceptable for applications where faster protection is beneficial. Tape & Reel packaging is standard for production environments.

Secondary Recommendation - Cross-Manufacturer Equivalent: 045101.5MRL (Littelfuse Inc., NANO²® 451 series) is suitable for designs requiring active production support with established supply chains. Electrical ratings match the SSQ 1.5 completely. The higher Melting I²t (0.853) results in slower thermal response compared to the original part; this must be verified against application thermal protection requirements. Active product status ensures long-term availability.

Alternative for Higher Voltage Applications: 047601.6MR (Littelfuse Inc., NANO²® 476 series) is applicable only when the circuit design permits higher AC voltage rating (250 V AC) or higher current rating (1.6 A). This part provides increased breaking capacity (100 A AC, 300 A DC) and is not a direct substitute but rather an upgraded variant for circuits with higher voltage or current margins.

SCHURTER Inc. Options: 3404.0047.22 and 3404.0047.11 (OMF 125 series) provide electrical equivalence with identical 1.5 A and 125 V AC/DC ratings. The J-Lead package configuration differs from the Square End Block of the SSQ 1.5, requiring PCB layout verification. The significantly lower Melting I²t (0.24) indicates much faster thermal response and may not be suitable for all applications without thermal analysis. These parts are suitable only when PCB footprint compatibility with J-Lead configuration is confirmed.

Obsolete Part Consideration: SSQ 1.5/5K is a parametric equivalent within the same Bel Fuse Inc. SSQ series but is also Obsolete. This part should not be selected for new designs requiring long-term supply assurance.

Frequently Asked Questions (FAQ)

Q: Can I use 045101.5MRL as a direct replacement for SSQ 1.5? A: Yes, 045101.5MRL is electrically compatible with identical 1.5 A and 125 V AC/DC ratings. The higher Melting I²t (0.853 vs. 0.57) means slower thermal response. Verify that your application's thermal protection requirements accommodate this difference. The 2-SMD, Square End Block package is mechanically compatible.

Q: What is the difference between 0679L1500-01 and SSQ 1.5? A: Both are Bel Fuse Inc. products with identical electrical ratings and breaking capacity. The 0679L1500-01 has a lower Melting I²t (0.29 vs. 0.57), providing faster thermal response. The 0679L1500-01 is Active production status, while SSQ 1.5 is Obsolete. Height dimension differs slightly (2.79 mm vs. 2.54 mm). Packaging format differs (Tape & Reel vs. Cut Tape & Digi-Reel®).

Q: Can I use 3404.0047.22 instead of SSQ 1.5? A: Electrical ratings are identical (1.5 A, 125 V AC/DC). However, the package/case is 2-SMD, J-Lead instead of 2-SMD, Square End Block. This requires PCB footprint verification before substitution. The significantly lower Melting I²t (0.24) indicates much faster thermal response and must be evaluated against application requirements.

Q: Why does 047601.6MR have different current and voltage ratings? A: 047601.6MR is a higher-rated variant (1.6 A, 250 V AC) designed for applications requiring increased voltage or current margins. It is not a direct substitute but rather an upgraded option when circuit design permits higher ratings. Use only when your application specifications allow for these higher values.

Q: What does Melting I²t mean, and why does it vary between substitutes? A: Melting I²t is a thermal characteristic that determines how quickly a fuse responds to overcurrent. Lower values indicate faster response. Substitutes with different Melting I²t values provide different thermal protection speeds. Verify that the substitute's thermal response is acceptable for your specific circuit protection requirements.

Q: Are all substitute parts RoHS3 compliant? A: Yes, all listed substitute parts are ROHS3 Compliant. All parts are also REACH Unaffected and classified as EAR99 for export control purposes.

Q: What is the difference between Cut Tape (CT) & Digi-Reel® and Tape & Reel (TR) packaging? A: Cut Tape (CT) & Digi-Reel® is a flexible packaging format suitable for lower-volume or mixed-component orders. Tape & Reel (TR) is standard production packaging for high-volume automated assembly. Both formats contain the same component; packaging choice depends on procurement volume and assembly process requirements.

Q: Can I substitute SSQ 1.5 with SSQ 1.5/5K? A: Both parts are parametric equivalents with identical electrical and mechanical specifications. However, both are Obsolete status. For new designs or long-term supply assurance, select an Active production substitute such as 0679L1500-01 or 045101.5MRL instead.

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