MF-RX375-AP-99 Equivalent & Substitute Parts

Part Overview

The MF-RX375-AP-99 is a Polymeric PTC Resettable Fuse manufactured by Bourns Inc. in the Multifuse® MF-RX series. This component is rated for 60V maximum voltage with a 3.75A hold current and is designed for through-hole radial mounting in disc configuration. The part is currently listed as obsolete, making identification of compatible substitute components essential for ongoing system support and procurement planning.

Substiute Parts

MF-RX375-AP-99

Bourns Inc.In Stock: 795MF-RX375-AP-99 Datasheet

Current PartRFQ

MF-RX375/72-AP

Bourns Inc.In Stock: 856MF-RX375/72-AP Datasheet

DirectRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for PTC resettable fuses is determined by the following critical parameters:

Voltage Rating: The substitute must meet or exceed the maximum voltage requirement of the application. The MF-RX375-AP-99 operates at 60V maximum.

Current Characteristics: The hold current (Ih), trip current (It), and maximum current must align with circuit protection requirements. The MF-RX375-AP-99 specifies 3.75A hold current and 7.5A trip current.

Resistance Profile: Initial resistance (Ri) and post-trip resistance (R1) determine voltage drop and thermal behavior. These values must be compatible with system design parameters.

Mounting and Physical Form Factor: Through-hole radial disc configuration with 0.402" lead spacing is required for PCB compatibility.

Thermal and Environmental Ratings: Operating temperature range of -40°C to 85°C and MSL rating must be maintained.

Regulatory Compliance: cURus and TUV approvals, ROHS3 compliance, and REACH status must be preserved.

The identified substitute MF-RX375/72-AP shares the same hold current (3.75A), trip current (7.5A), initial resistance (30 mOhms), post-trip resistance (80 mOhms), time to trip (24s), mounting type, lead spacing, thermal range, and regulatory certifications. The primary difference is the maximum voltage rating of 72V versus 60V.

Parameter Comparison

Engineering Selection Recommendations

The MF-RX375/72-AP is a direct functional substitute for the obsolete MF-RX375-AP-99. Both components are manufactured by Bourns Inc. within the Multifuse® MF-RX family and maintain identical electrical characteristics for hold current, trip current, resistance profiles, and response time.

The MF-RX375/72-AP carries active product status, ensuring ongoing availability and supply chain continuity. Both parts maintain equivalent regulatory certifications (cURus, TUV), ROHS3 compliance, and REACH status.

The 72V maximum voltage rating of the substitute exceeds the 60V requirement of the original part, providing enhanced voltage margin for applications operating at or below 60V. Physical form factor, lead spacing, and mounting configuration are identical, enabling direct PCB compatibility without layout modifications.

Frequently Asked Questions (FAQ)

Q: Can the MF-RX375/72-AP replace the MF-RX375-AP-99 in existing designs?

A: Yes. The substitute maintains identical hold current (3.75A), trip current (7.5A), resistance characteristics, time to trip, operating temperature range, mounting type, and lead spacing. The higher voltage rating (72V vs. 60V) is compatible with applications designed for 60V operation.

Q: What is the primary difference between these two parts?

A: The maximum voltage rating differs: MF-RX375-AP-99 is rated for 60V, while MF-RX375/72-AP is rated for 72V. All other electrical and mechanical parameters are identical.

Q: Are there packaging differences between the main part and substitute?

A: The MF-RX375-AP-99 packaging is listed as standard, while the MF-RX375/72-AP is supplied in Tape & Box (TB) format. Both use identical radial disc through-hole configuration with 0.402" lead spacing.

Q: Do both parts meet the same regulatory requirements?

A: Yes. Both components carry cURus and TUV approvals, are ROHS3 compliant, and have REACH Unaffected status.

Q: Why is the original part listed as obsolete?

A: The MF-RX375-AP-99 is obsolete, but the MF-RX375/72-AP remains in active production, providing a viable path for continued component procurement and system support.