Equivalent & Substitute Parts for MF-MSMD125-2

Part Overview

The MF-MSMD125-2 is a Polymeric PTC Resettable Fuse rated at 6V, 1.25A hold current, manufactured by Bourns Inc. in the 1812 (4532 Metric) surface mount package. This part is classified as Obsolete, making identification of equivalent and substitute components essential for ongoing design support and production continuity. Substitute parts must maintain electrical compatibility across voltage, current hold, and thermal characteristics while accommodating modern packaging and compliance requirements.

Substiute Parts

MF-MSMD125-2

Bourns Inc.In Stock: 880MF-MSMD125-2 Datasheet

Current PartRFQ

MF-MSMF125-2

Bourns Inc.In Stock: 84303MF-MSMF125-2 Datasheet

DirectRFQ

MF-MSMF150-2

Bourns Inc.In Stock: 12810MF-MSMF150-2 Datasheet

DirectRFQ

PFMF.125.2

SCHURTER Inc.In Stock: 1749PFMF.125.2 Datasheet

DirectRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the MF-MSMD125-2 is determined by the following critical parameters:

• Voltage Rating: All substitutes must maintain 6V maximum voltage rating
• Current Hold (Ih): Substitutes must support 1.25A hold current or higher
• Current Trip (It): Trip current must remain at 2.5A or proportionally scaled with hold current
• Package Compatibility: Surface mount 1812 (4532 Metric) package required
• Thermal Performance: Operating temperature range -40°C to 85°C must be maintained
• Resistance Characteristics: Initial resistance minimum 35 mOhms and post-trip resistance maximum 140 mOhms define electrical behavior

Substitutes are grouped into two categories:

Category 1 - Direct Electrical Equivalents (Same Ih/It Rating): Parts maintaining identical 1.25A hold current and 2.5A trip current specifications.

Category 2 - Higher Current Rating Alternatives (Elevated Ih/It Rating): Parts with increased hold and trip current ratings suitable for applications requiring higher fault tolerance.

Parameter Comparison

Engineering Selection Recommendations

MF-MSMF125-2 (Bourns Inc.) is the primary substitute for MF-MSMD125-2. This part maintains identical electrical specifications (6V, 1.25A Ih, 2.5A It, 400 ms trip time) and package form factor. The MF-MSMF125-2 is Active status with ROHS3 compliance and modern certifications (cURus, TUV), providing direct replacement capability with improved regulatory standing. Packaging is available in Tape & Reel format.

MF-MSMF150-2 (Bourns Inc.) serves as a higher-current alternative when circuit design permits elevated fault tolerance. This part increases hold current to 1.5A and trip current to 3A while maintaining 6V rating and 1812 package compatibility. The extended trip time of 500 ms and reduced post-trip resistance (120 mOhms maximum) reflect the higher current rating. Selection of this part requires circuit-level verification that the increased trip threshold does not compromise protection objectives.

PFMF.125.2 (SCHURTER Inc.) provides an alternative source for 1.25A hold current specification. Electrical parameters match MF-MSMD125-2 exactly (6V, 1.25A Ih, 2.5A It, 400 ms trip time, 35 mOhms initial resistance, 140 mOhms post-trip resistance). This part is Active status with ROHS3 compliance and cURus/TUV certifications. Cross-manufacturer substitution is supported by identical electrical and thermal characteristics.

Frequently Asked Questions (FAQ)

Q: Can MF-MSMF125-2 directly replace MF-MSMD125-2 in production?

A: Yes. MF-MSMF125-2 maintains all critical electrical parameters: 6V voltage rating, 1.25A hold current, 2.5A trip current, 400 ms trip time, and identical resistance specifications. Both use 1812 (4532 Metric) surface mount package. The primary difference is product status (Active vs. Obsolete) and improved RoHS3 compliance.

Q: What is the difference between MF-MSMF125-2 and MF-MSMF150-2?

A: MF-MSMF150-2 increases hold current from 1.25A to 1.5A and trip current from 2.5A to 3A. Trip time extends from 400 ms to 500 ms. Post-trip resistance improves to 120 mOhms maximum. These changes reflect higher fault current tolerance. Circuit verification is required before substitution to confirm the elevated trip threshold remains acceptable for protection requirements.

Q: Is PFMF.125.2 electrically equivalent to MF-MSMD125-2?

A: Yes. PFMF.125.2 matches all electrical specifications: 6V maximum voltage, 1.25A hold current, 2.5A trip current, 400 ms trip time, 35 mOhms initial resistance, and 140 mOhms post-trip resistance. Operating temperature range and 1812 package are identical. PFMF.125.2 represents a cross-manufacturer alternative from SCHURTER Inc.

Q: What packaging formats are available for substitute parts?

A: MF-MSMF125-2 is supplied in Tape & Reel (TR) format. MF-MSMF150-2 is available in Cut Tape (CT) and Digi-Reel format. PFMF.125.2 is supplied in Tape & Reel (TR) format. Packaging selection depends on production volume and assembly line requirements.

Q: Are all substitute parts RoHS compliant?

A: MF-MSMF125-2, MF-MSMF150-2, and PFMF.125.2 are all ROHS3 compliant. The original MF-MSMD125-2 is RoHS non-compliant. Substitution with any of these parts improves regulatory compliance for new designs and production runs.

Q: What certifications do the substitute parts carry?

A: MF-MSMF125-2 and MF-MSMF150-2 carry cURus and TUV certifications. PFMF.125.2 carries cURus and TUV certifications. The original MF-MSMD125-2 carries CSA, TUV, and UR certifications. Certification differences should be evaluated against specific application and regional requirements.