MF-R040-2-99 Equivalent & Substitute Parts

Part Overview

The MF-R040-2-99 is a Polymeric PTC Resettable Fuse manufactured by Bourns Inc. in the Multifuse® MF-R series. This component is rated for 60V maximum voltage with a 400 mA hold current and 800 mA trip current, designed for through-hole radial mounting in disc configuration. The part is currently listed as Obsolete, making identification of equivalent and substitute components essential for ongoing design support and procurement.

Substiute Parts

MF-R040-2-99

Bourns Inc.In Stock: 949MF-R040-2-99 Datasheet

Current PartRFQ

MF-R040-2

Bourns Inc.In Stock: 1873MF-R040-2 Datasheet

Parametric EquivalentRFQ

MF-R040-2-17

Bourns Inc.In Stock: 1034MF-R040-2-17 Datasheet

Parametric EquivalentRFQ

RXEF017-AP

LittelfuseIn Stock: 1385RXEF017-AP Datasheet

SimilarRFQ

PFRA.040.2

SCHURTER Inc.In Stock: 858PFRA.040.2 Datasheet

Parametric EquivalentRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution for the MF-R040-2-99 is determined by strict electrical and mechanical parameter matching. The critical parameters that define substitutability are:

Electrical Parameters:

• Voltage rating: 60V maximum
• Hold current (Ih): 400 mA
• Trip current (It): 800 mA
• Initial resistance (Ri): 520 mOhms minimum
• Post-trip resistance (R1): 1.29 Ohms maximum

Mechanical Parameters:

• Mounting type: Through Hole
• Package configuration: Radial, Disc
• Physical dimensions: 0.291" Dia x 0.122" T (7.40mm x 3.10mm)
• Lead spacing: 0.201" (5.10mm)

Compliance Parameters:

• RoHS3 compliance
• Operating temperature: -40°C ~ 85°C

Substitute parts are classified into two categories:

Parametric Equivalents: Parts with identical electrical specifications, mechanical form factor, and lead spacing. These include MF-R040-2, MF-R040-2-17, and PFRA.040.2.

Similar Parts: Parts with the same voltage rating and mounting configuration but different current ratings. The RXEF017-AP from Littelfuse is classified as a similar part due to its lower hold current (170 mA vs. 400 mA) and different resistance characteristics.

Parameter Comparison

Engineering Selection Recommendations

Primary Substitutes (Parametric Equivalents):

MF-R040-2, MF-R040-2-17, and PFRA.040.2 are direct parametric equivalents to the MF-R040-2-99. All three parts maintain identical electrical specifications (60V, 400 mA hold current, 800 mA trip current) and mechanical form factors. The primary differences are product status and packaging format.

MF-R040-2 and MF-R040-2-17 are both Active products from Bourns Inc., making them the preferred choices for new designs and ongoing procurement. MF-R040-2-17 carries additional AEC-Q200 automotive qualification and expanded approval agency certifications (cUL, cURus, TUV, UL), providing enhanced compliance documentation. PFRA.040.2 from SCHURTER Inc. is also Active and maintains full parametric equivalence with identical resistance characteristics and thermal operating range.

Secondary Substitute (Similar Part):

RXEF017-AP from Littelfuse is classified as a similar part rather than a direct equivalent due to its reduced hold current specification (170 mA vs. 400 mA) and significantly higher resistance values (3.3 Ohms initial, 8 Ohms post-trip vs. 520 mOhms and 1.29 Ohms respectively). This part is suitable only for applications where the lower current rating and higher resistance are acceptable design parameters. Physical dimensions are nearly identical with only minor thickness variation (0.118" vs. 0.122").

All substitute parts maintain ROHS3 compliance and the full -40°C to 85°C operating temperature range of the original component.

Frequently Asked Questions (FAQ)

Q: Can MF-R040-2 be used as a direct replacement for MF-R040-2-99?

A: Yes. MF-R040-2 is a parametric equivalent with identical electrical specifications (60V, 400 mA hold current, 800 mA trip current) and mechanical configuration. The primary difference is that MF-R040-2-99 is Obsolete while MF-R040-2 is Active. MF-R040-2 is available in Cut Tape packaging.

Q: What is the difference between MF-R040-2 and MF-R040-2-17?

A: Both parts are parametric equivalents with identical electrical and mechanical specifications. The key differences are packaging format (MF-R040-2 is Cut Tape; MF-R040-2-17 is Tape & Reel) and certifications. MF-R040-2-17 includes AEC-Q200 automotive qualification and additional approval agencies (cUL, cURus, TUV, UL vs. cURus, TUV for MF-R040-2).

Q: Is PFRA.040.2 from SCHURTER a suitable replacement?

A: Yes. PFRA.040.2 is a parametric equivalent with identical electrical specifications and mechanical form factor. It maintains the same 60V rating, 400 mA hold current, 800 mA trip current, and resistance characteristics. PFRA.040.2 is an Active product available in Cut Tape packaging.

Q: Can RXEF017-AP from Littelfuse replace the MF-R040-2-99?

A: RXEF017-AP is not a direct equivalent due to its lower hold current (170 mA vs. 400 mA) and significantly higher resistance values. It is suitable only for applications where these different electrical characteristics are acceptable. Physical dimensions are nearly identical, with only minor thickness variation.

Q: What are the key parameters that determine substitutability?

A: The critical parameters are voltage rating (60V), hold current (400 mA), trip current (800 mA), initial resistance (520 mOhms minimum), post-trip resistance (1.29 Ohms maximum), mounting type (Through Hole), package configuration (Radial, Disc), and lead spacing (0.201" / 5.10mm). All parametric equivalents match these specifications exactly.

Q: Are all substitute parts RoHS3 compliant?

A: Yes. All substitute parts listed (MF-R040-2, MF-R040-2-17, PFRA.040.2, and RXEF017-AP) are ROHS3 compliant and maintain the -40°C to 85°C operating temperature range.

Q: What packaging options are available for the parametric equivalents?

A: MF-R040-2 is available in Cut Tape (CT) packaging. MF-R040-2-17 is available in Tape & Reel (TR) packaging. PFRA.040.2 is available in Cut Tape (CT) packaging. Packaging selection depends on procurement volume and assembly process requirements.