MF-SM050-2-99 Equivalent & Substitute Parts

Part Overview

The MF-SM050-2-99 is a Polymeric PTC Resettable Fuse manufactured by Bourns Inc. in the Multifuse® MF-SM series. This component is rated for 60V maximum voltage with 500 mA hold current and is designed for surface mount applications in 2-SMD package configuration. The part is currently listed as Obsolete, making equivalent and substitute parts necessary for ongoing design support and procurement.

Key Parameters

Parameter	Value
Voltage - Max	60V
Current - Hold (Ih) (Max)	500 mA
Current - Trip (It)	1 A
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	2-SMD
Type	Polymeric
Time to Trip	4 s

Substitute Part Grouping Explanation

Substitution eligibility for the MF-SM050-2-99 is determined by the following critical parameters:

Voltage rating of 60V maximum
Hold current (Ih) of 500 mA maximum
Trip current (It) of 1 A
Initial resistance (Ri) minimum of 350 mOhms
Post-trip resistance (R1) maximum of 1.4 Ohms
Operating temperature range of -40°C to 85°C
Surface mount configuration in 2-SMD package
Polymeric PTC resettable fuse type

All substitute parts listed maintain these electrical and mechanical specifications, ensuring functional equivalence within the defined parameter tolerances.

Parameter Comparison

Parameter	MF-SM050-2-99	MF-SM050-2	MF-SM050-2-006	MF-SM050/60-2	PFSM.050.2	SMD050F-2
Manufacturer	Bourns Inc.	Bourns Inc.	Bourns Inc.	Bourns Inc.	SCHURTER Inc.	Littelfuse Inc.
Voltage - Max	60V	60V	60V	60V	60V	60V
Current - Hold (Ih) (Max)	500 mA	500 mA	500 mA	500 mA	500 mA	500 mA
Current - Trip (It)	1 A	1 A	1 A	1 A	1 A	1 A
Resistance - Initial (Ri) (Min)	350 mOhms	350 mOhms	350 mOhms	350 mOhms	350 mOhms	350 mOhms
Resistance - Post Trip (R1) (Max)	1.4 Ohms	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	-40°C ~ 85°C
Mounting Type	Surface Mount	Surface Mount	Surface Mount	Surface Mount	Surface Mount	Surface Mount
Package / Case	2-SMD	2-SMD	2-SMD	2-SMD	2-SMD	2-SMD
Type	Polymeric	Polymeric	Polymeric	Polymeric	Polymeric	Polymeric
Time to Trip	4 s	4 s	4 s	4 s	4 s	4 s
Product Status	Obsolete	Active	Active	Active	Active	Active
RoHS Status	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant
Approval Agency	cURus, TUV	cURus, TUV	cURus, TUV	cURus, TUV	cURus, TUV	CSA, TUV, UL

Engineering Selection Recommendations

All listed substitute parts maintain electrical and mechanical equivalence to the MF-SM050-2-99 across the critical parameters that define functional compatibility. Selection among active alternatives should be based on:

Bourns Inc. Multifuse® MF-SM Series (MF-SM050-2, MF-SM050-2-006, MF-SM050/60-2): These parts are direct parametric equivalents from the original manufacturer. MF-SM050-2 and MF-SM050/60-2 are available in higher inventory quantities. All three maintain AEC-Q200 ratings and cURus/TUV approvals consistent with the obsolete part.

SCHURTER Inc. PFSM.050.2: This part provides cross-manufacturer equivalence with identical electrical specifications. It carries cURus and TUV approvals and is available in active production status with 1,811 units in stock.

Littelfuse Inc. SMD050F-2: This PolySwitch® series alternative meets all electrical and mechanical requirements. It offers the highest inventory availability (22,214 units) and includes CSA, TUV, and UL approvals. Physical dimensions vary slightly (0.290" L x 0.202" W versus 0.287" L x 0.214" W), remaining within 2-SMD package compatibility.

All substitute parts are ROHS3 compliant and REACH unaffected, maintaining regulatory compliance with the original specification.

Frequently Asked Questions (FAQ)

Q: Can MF-SM050-2 directly replace MF-SM050-2-99 in existing designs?

A: Yes. MF-SM050-2 is a parametric equivalent from Bourns Inc. with identical electrical specifications (60V, 500 mA hold current, 1 A trip current, 350 mOhms initial resistance, 1.4 Ohms post-trip resistance) and the same 2-SMD surface mount package. The primary difference is product status: MF-SM050-2 is active while MF-SM050-2-99 is obsolete.

Q: What is the difference between MF-SM050-2, MF-SM050-2-006, and MF-SM050/60-2?

A: All three are Bourns Inc. Multifuse® MF-SM series parts with identical electrical and mechanical specifications. Differences are in packaging format (Cut Tape & Digi-Reel® versus Tape & Reel) and inventory availability. Selection depends on procurement requirements and supply chain preferences.

Q: Can PFSM.050.2 from SCHURTER be used as a substitute?

A: Yes. PFSM.050.2 maintains all critical electrical parameters (60V, 500 mA hold current, 1 A trip current, 350 mOhms initial resistance, 1.4 Ohms post-trip resistance) and 2-SMD package configuration. Physical dimensions are 0.289" L x 0.214" W, compared to 0.287" L x 0.214" W for the original part, representing a negligible difference within standard PCB layout tolerances.

Q: Is SMD050F-2 from Littelfuse compatible with the MF-SM050-2-99?

A: Yes. SMD050F-2 meets all electrical specifications and operates within the same -40°C to 85°C temperature range. Physical dimensions are 0.290" L x 0.202" W, a minor variation from the original 0.287" L x 0.214" W. Both are 2-SMD surface mount packages suitable for equivalent PCB placement. SMD050F-2 offers the highest inventory availability among all substitutes.

Q: What certifications should I verify for regulatory compliance?

A: All substitute parts maintain ROHS3 compliance and REACH unaffected status. Bourns parts carry cURus and TUV approvals. Littelfuse SMD050F-2 includes CSA, TUV, and UL approvals, providing additional certification coverage. Verify specific approval requirements for your application before final selection.

Q: Are there any differences in moisture sensitivity between substitutes?

A: MF-SM050-2-99, MF-SM050-2, MF-SM050-2-006, and MF-SM050/60-2 all have MSL 1 (Unlimited). PFSM.050.2 has MSL Not Applicable. SMD050F-2 has MSL 2A (4 Weeks). These differences do not affect functional equivalence but may impact storage and handling procedures.

Request Quote (Ships tomorrow)

Part Number

Quantity

Company

Contact Name

E-mail

Message