MF-RX250-2-99 Equivalent & Substitute Parts

Part Overview

The MF-RX250-2-99 is a Polymeric PTC Resettable Fuse manufactured by Bourns Inc. as part of the Multifuse® MF-RX series. This through-hole radial disc component is rated for 60V maximum voltage with a 2.5A hold current. The product is currently classified as Obsolete, making identification of compatible substitute parts essential for ongoing design support and procurement.

Substiute Parts

MF-RX250-2-99

Bourns Inc.In Stock: 839MF-RX250-2-99 Datasheet

Current PartRFQ

MF-RX250/72-0

Bourns Inc.In Stock: 4130MF-RX250/72-0 Datasheet

DirectRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the MF-RX250-2-99 is determined by the following critical parameters:

Mechanical Compatibility: Mounting type (Through Hole), package type (Radial, Disc), physical dimensions (0.839" L x 0.122" W, 1.039" seated height), and lead spacing (0.402") must remain identical to ensure PCB footprint compatibility.

Electrical Compatibility: Current hold rating (Ih) of 2.5A and current trip rating (It) of 5A are the primary functional specifications. Voltage rating may be equal to or greater than the original 60V maximum, as higher voltage-rated components operate safely in lower voltage applications. Initial resistance (Ri) and post-trip resistance (R1) must fall within the specified ranges to maintain circuit protection characteristics.

Regulatory & Environmental: RoHS3 compliance, cURus and TUV approvals, and REACH unaffected status ensure continued regulatory acceptance. Operating temperature range of -40°C to 85°C must be maintained.

Parameter Comparison

Engineering Selection Recommendations

The MF-RX250/72-0 is a direct functional and mechanical substitute for the obsolete MF-RX250-2-99. Both components share identical electrical characteristics (2.5A hold current, 5A trip current, 15.6s trip time, 50mOhms initial resistance, 130mOhms post-trip resistance) and mechanical specifications (through-hole radial disc package, identical dimensions and lead spacing).

The primary distinction is voltage rating: the MF-RX250/72-0 is rated for 72V maximum compared to the original 60V rating. This higher voltage rating does not compromise performance in 60V applications and provides additional design margin.

Both components maintain identical regulatory compliance: ROHS3 certification, cURus and TUV approvals, REACH unaffected status, and MSL 1 (unlimited) moisture sensitivity level. The substitute part is currently in active production status, ensuring long-term availability and supply chain stability compared to the obsolete original part.

Frequently Asked Questions (FAQ)

Q: Can MF-RX250/72-0 be used as a direct replacement for MF-RX250-2-99?

A: Yes. The MF-RX250/72-0 is mechanically and electrically compatible. All critical parameters including current ratings, resistance values, trip time, operating temperature range, and physical dimensions are identical. The higher voltage rating (72V vs. 60V) does not affect operation in 60V circuits.

Q: What is the significance of the voltage rating difference?

A: The MF-RX250/72-0 is rated for 72V maximum, while the original MF-RX250-2-99 is rated for 60V. A component rated for higher voltage operates safely at lower voltages. This difference does not impact the component's protective function or electrical characteristics in your application.

Q: Are the physical dimensions identical?

A: Yes. Both components have identical through-hole radial disc package specifications: 0.839" length x 0.122" width, 1.039" seated height, and 0.402" lead spacing. PCB footprints are interchangeable.

Q: Do both parts meet the same regulatory requirements?

A: Yes. Both the MF-RX250-2-99 and MF-RX250/72-0 are ROHS3 compliant, carry cURus and TUV approvals, and have REACH unaffected status. Regulatory compliance is maintained with the substitute part.

Q: Why is the original part obsolete?

A: The MF-RX250-2-99 is classified as obsolete by the manufacturer. The MF-RX250/72-0 remains in active production, providing a current alternative for new designs and ongoing production support.

Q: Are the electrical protection characteristics identical?

A: Yes. Both components have identical hold current (2.5A), trip current (5A), trip time (15.6s), initial resistance (50mOhms minimum), and post-trip resistance (130mOhms maximum). Protection behavior is functionally equivalent.