SMD050-2 Equivalent & Substitute Parts

Part Overview

The SMD050-2 is a Polymeric PTC Resettable Fuse manufactured by Littelfuse Inc., rated for 60V maximum voltage with a 500 mA hold current. This component is classified as Obsolete, making equivalent and substitute parts necessary for ongoing design support and procurement. The SMD050-2 operates across a temperature range of -40°C to 85°C and is housed in a 2920 (7351 Metric) surface mount package. Substitute parts must maintain electrical equivalence across voltage, current, and thermal characteristics while accommodating modern packaging and compliance requirements.

Key Parameters

Parameter	Value
Voltage - Max	60V
Current - Hold (Ih) (Max)	500 mA
Current - Trip (It)	1 A
Current - Max	10 A
Time to Trip	4 s
Resistance - Initial (Ri) (Min)	350 mOhms
Resistance - Post Trip (R1) (Max)	1.4 Ohms
Operating Temperature	-40°C ~ 85°C
Mounting Type	Surface Mount
Package / Case	2920 (7351 Metric)
Type	Polymeric

Substitute Part Grouping Explanation

Substitute parts for the SMD050-2 are qualified based on the following electrical and mechanical parameters:

Electrical Equivalence Criteria:

Voltage - Max: 60V (exact match required)
Current - Hold (Ih) (Max): 500 mA (exact match required)
Current - Trip (It): 1 A (exact match required)
Time to Trip: 4 s (exact match required)
Resistance - Initial (Ri) (Min): 350 mOhms or lower (acceptable tolerance)
Resistance - Post Trip (R1) (Max): 1.4 Ohms (exact match required)
Operating Temperature: -40°C ~ 85°C (exact match required)

Mechanical Compatibility Criteria:

Mounting Type: Surface Mount (required)
Package / Case: 2920 (7351 Metric) or 2-SMD equivalent footprint (acceptable)
Type: Polymeric (required)

All substitute parts listed maintain these core electrical parameters and are compatible with the original application requirements.

Parameter Comparison

Parameter	SMD050-2 (Main)	SMD050F-2	2920L050DR	MF-SM050-2	0ZCF0050FF2C
Manufacturer	Littelfuse Inc.	Littelfuse Inc.	Littelfuse Inc.	Bourns Inc.	Bel Fuse Inc.
Voltage - Max	60V	60V	60V	60V	60V
Current - Hold (Ih) (Max)	500 mA	500 mA	500 mA	500 mA	500 mA
Current - Trip (It)	1 A	1 A	1 A	1 A	1 A
Current - Max	10 A	10 A	10 A	40 A	100 A
Time to Trip	4 s	4 s	4 s	4 s	4 s
Resistance - Initial (Ri) (Min)	350 mOhms	350 mOhms	350 mOhms	350 mOhms	300 mOhms
Resistance - Post Trip (R1) (Max)	1.4 Ohms	1.4 Ohms	1.4 Ohms	1.4 Ohms	1.4 Ohms
Operating Temperature	-40°C ~ 85°C	-40°C ~ 85°C	-40°C ~ 85°C	-40°C ~ 85°C	-40°C ~ 85°C
Mounting Type	Surface Mount	Surface Mount	Surface Mount	Surface Mount	Surface Mount
Package / Case	2920 (7351 Metric)	2-SMD	2920 (7351 Metric), Concave	2-SMD	2920 (7351 Metric), Concave
Type	Polymeric	Polymeric	Polymeric	Polymeric	Polymeric
Product Status	Obsolete	Active	Active	Active	Active
RoHS Status	RoHS non-compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant
Approval Agency	CSA, TUV, UL	CSA, TUV, UL	cURus, TUV	cURus, TUV	AEC-Q200, cURus, TUV
Moisture Sensitivity Level (MSL)	2A (4 Weeks)	2A (4 Weeks)	2A (4 Weeks)	1 (Unlimited)	2A (4 Weeks)

Engineering Selection Recommendations

SMD050F-2 (Littelfuse Inc.): Direct electrical and mechanical equivalent with identical specifications. Product status is Active with ROHS3 compliance. Recommended as the primary substitute for the obsolete SMD050-2 when 2-SMD packaging is acceptable. Maintains all electrical parameters and certifications.

2920L050DR (Littelfuse Inc.): Manufacturer-recommended substitute with identical electrical specifications. Product status is Active with ROHS3 compliance. Package is 2920 (7351 Metric) Concave, maintaining footprint compatibility with the original SMD050-2. Thickness is reduced to 0.049" (1.25mm) compared to the original 0.125" (3.18mm), which may affect board assembly clearance considerations.

MF-SM050-2 (Bourns Inc.): Electrical equivalent with identical core parameters. Product status is Active with ROHS3 compliance and AEC-Q200 rating. Moisture Sensitivity Level is 1 (Unlimited), providing superior moisture handling compared to the original 2A (4 Weeks). Package is 2-SMD with slightly larger dimensions (0.287" L x 0.214" W versus 0.290" L x 0.202" W). Current - Max rating is 40 A, exceeding the original 10 A specification.

0ZCF0050FF2C (Bel Fuse Inc.): Manufacturer-recommended substitute with identical electrical specifications. Product status is Active with ROHS3 compliance and AEC-Q200 rating. Package is 2920 (7351 Metric) Concave with reduced thickness of 0.045" (1.15mm). Resistance - Initial (Ri) (Min) is 300 mOhms, which is lower than the original 350 mOhms specification. Current - Max rating is 100 A, significantly exceeding the original 10 A specification.

Frequently Asked Questions (FAQ)

Q: Can SMD050F-2 be used as a direct replacement for SMD050-2?

A: Yes. SMD050F-2 maintains identical electrical specifications including voltage, hold current, trip current, and time to trip. The primary difference is packaging format (2-SMD versus 2920 Metric), which requires footprint verification on the target PCB. Both parts are Polymeric PTC Resettable Fuses with equivalent performance characteristics.

Q: What is the difference between 2920 (7351 Metric) and 2-SMD packaging?

A: Both are surface mount packages for Polymeric PTC Resettable Fuses. The 2920 (7351 Metric) designation refers to the physical dimensions in metric format (7.36mm x 5.12mm). The 2-SMD designation indicates a two-terminal surface mount device with similar footprint dimensions. PCB layout compatibility must be verified before substitution.

Q: Why is the SMD050-2 listed as Obsolete?

A: The SMD050-2 is no longer in active production. All substitute parts listed (SMD050F-2, 2920L050DR, MF-SM050-2, 0ZCF0050FF2C) are Active products with current manufacturing support and improved compliance ratings (ROHS3).

Q: Are all substitute parts RoHS3 compliant?

A: Yes. All substitute parts listed are ROHS3 compliant. The original SMD050-2 is RoHS non-compliant. Substitution to any of the listed parts will improve regulatory compliance for new designs or production runs.

Q: What is the significance of the Concave package designation on 2920L050DR and 0ZCF0050FF2C?

A: The Concave designation indicates a specific surface profile on the component. This affects board assembly and clearance considerations. Verify that the target PCB design accommodates the Concave profile before substitution.

Q: Can MF-SM050-2 be used in automotive applications?

A: MF-SM050-2 carries AEC-Q200 rating and is suitable for automotive applications. The original SMD050-2 does not carry this rating. If automotive qualification is required, MF-SM050-2 is the appropriate choice among the substitute options.

Q: What is the impact of different Moisture Sensitivity Levels (MSL)?

A: MF-SM050-2 has MSL 1 (Unlimited), meaning it can be stored indefinitely without moisture absorption concerns. Other substitutes have MSL 2A (4 Weeks), requiring controlled storage conditions. For applications with extended shelf life requirements, MF-SM050-2 provides superior moisture handling.

Q: Are there differences in initial resistance between substitute parts?

A: 0ZCF0050FF2C has Resistance - Initial (Ri) (Min) of 300 mOhms, compared to 350 mOhms for the original SMD050-2 and other substitutes. This lower initial resistance may result in slightly different circuit behavior during normal operation. Verify circuit performance if this part is selected.

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