MF-R040-0-99 Equivalent & Substitute Parts

Part Overview

The MF-R040-0-99 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 equivalent and substitute parts necessary for ongoing design support and procurement.

Key Parameters

Parameter	Value
Voltage - Max	60V
Current - Hold (Ih) (Max)	400 mA
Current - Trip (It)	800 mA
Current - Max	40 A
Time to Trip	3.8 s
Resistance - Initial (Ri) (Min)	520 mOhms
Resistance - Post Trip (R1) (Max)	1.29 Ohms
Operating Temperature	-40°C ~ 85°C
Mounting Type	Through Hole
Package / Case	Radial, Disc
Size / Dimension	0.291" Dia x 0.122" T (7.40mm x 3.10mm)
Lead Spacing	0.201" (5.10mm)
RoHS Status	ROHS3 Compliant

Substitute Part Grouping Explanation

Substitution eligibility for the MF-R040-0-99 is determined by the following critical parameters:

Voltage rating must be equal to or greater than 60V
Hold current (Ih) must be 400 mA
Trip current (It) must be 800 mA
Time to trip must be 3.8 s
Initial resistance (Ri) must be 520 mOhms minimum
Post-trip resistance (R1) must not exceed 1.29 Ohms
Operating temperature range must encompass -40°C to 85°C
Mounting type must be through-hole radial disc configuration
Physical dimensions and lead spacing must be compatible with PCB layouts designed for the original part

The substitute parts identified fall into two categories: parametric equivalents from the same manufacturer (Bourns MF-R series variants) and direct cross-manufacturer alternatives (Littelfuse RXEF and SCHURTER PFRA series).

Parameter Comparison

Parameter	MF-R040-0-99	MF-R040	MF-R040-0-17	RXEF040	PFRA.040
Manufacturer	Bourns Inc.	Bourns Inc.	Bourns Inc.	Littelfuse	SCHURTER Inc.
Product Status	Obsolete	Active	Active	Active	Active
Voltage - Max	60V	60V	60V	72V	60V
Current - Hold (Ih) (Max)	400 mA	400 mA	400 mA	400 mA	400 mA
Current - Trip (It)	800 mA	800 mA	800 mA	800 mA	800 mA
Current - Max	40 A	40 A	40 A	40 A	40 A
Time to Trip	3.8 s	3.8 s	3.8 s	3.8 s	3.8 s
Resistance - Initial (Ri) (Min)	520 mOhms	520 mOhms	520 mOhms	550 mOhms	520 mOhms
Resistance - Post Trip (R1) (Max)	1.29 Ohms	1.29 Ohms	1.29 Ohms	1.29 Ohms	1.29 Ohms
Operating Temperature	-40°C ~ 85°C	-40°C ~ 85°C	-40°C ~ 85°C	-40°C ~ 85°C	-40°C ~ 85°C
Mounting Type	Through Hole	Through Hole	Through Hole	Through Hole	Through Hole
Package / Case	Radial, Disc	Radial, Disc	Radial, Disc	Radial, Disc	Radial, Disc
Size / Dimension	0.291" Dia x 0.122" T (7.40mm x 3.10mm)	0.291" Dia x 0.122" T (7.40mm x 3.10mm)	0.291" Dia x 0.122" T (7.40mm x 3.10mm)	0.299" Dia x 0.118" T (7.60mm x 3.00mm)	0.291" Dia x 0.122" T (7.40mm x 3.10mm)
Lead Spacing	0.201" (5.10mm)	0.201" (5.10mm)	0.201" (5.10mm)	0.199" (5.05mm)	0.201" (5.10mm)
RoHS Status	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant
Approval Agency	cURus, TUV	cURus, TUV	cUL, cURus, TUV, UL	CQC, CSA, TUV, UL	cURus, TUV

Engineering Selection Recommendations

MF-R040 and MF-R040-0-17 are the primary recommended substitutes for the obsolete MF-R040-0-99. Both are active Bourns Multifuse® MF-R series components with identical electrical specifications and physical dimensions. MF-R040-0-17 offers enhanced regulatory compliance with cUL and UL certifications in addition to cURus and TUV, plus AEC-Q200 automotive qualification rating.

PFRA.040 from SCHURTER Inc. is a parametric equivalent with identical voltage, current, resistance, and temperature specifications. Physical dimensions and lead spacing match the original part exactly. Regulatory approvals include cURus and TUV certification.

RXEF040 from Littelfuse PolySwitch® series is a direct cross-manufacturer alternative with 72V maximum voltage rating, providing higher voltage margin than the original 60V specification. All other electrical parameters match the original part. Physical dimensions show minor variations: 0.299" diameter versus 0.291", and 0.118" thickness versus 0.122". Lead spacing is 0.199" versus 0.201". These dimensional differences are within typical PCB layout tolerances for radial through-hole components. Regulatory approvals include CQC, CSA, TUV, and UL certification.

Frequently Asked Questions (FAQ)

Q: Can MF-R040 be used as a direct replacement for MF-R040-0-99?

A: Yes. MF-R040 is an active Bourns product with identical electrical specifications, operating temperature range, and physical dimensions. The primary difference is product status: MF-R040-0-99 is obsolete while MF-R040 is in active production.

Q: What is the difference between MF-R040 and MF-R040-0-17?

A: Both parts share identical electrical specifications and physical dimensions. MF-R040-0-17 includes additional regulatory certifications (cUL and UL) and carries AEC-Q200 automotive qualification. Selection depends on application requirements for automotive compliance.

Q: Is RXEF040 compatible with designs using MF-R040-0-99?

A: RXEF040 meets all electrical specifications and operating temperature requirements. Physical dimensions show minor variations: diameter increases from 7.40mm to 7.60mm, thickness decreases from 3.10mm to 3.00mm, and lead spacing changes from 5.10mm to 5.05mm. These differences are within standard PCB layout tolerances for radial disc components. Verify PCB footprint clearances before implementation.

Q: Why does RXEF040 have a higher voltage rating (72V) than the original part (60V)?

A: Higher voltage ratings provide additional design margin and do not affect compatibility in 60V applications. The component will function correctly in circuits designed for 60V maximum operation.

Q: Can PFRA.040 replace MF-R040-0-99 in all applications?

A: Yes. PFRA.040 is a parametric equivalent with matching voltage, current, resistance, and temperature specifications. Physical dimensions and lead spacing are identical to the original part. Regulatory approvals (cURus, TUV) align with the original specification.

Q: What packaging options are available for these substitute parts?

A: MF-R040 is supplied in bulk packaging. MF-R040-0-17 is supplied in bulk packaging. RXEF040 is supplied in bag packaging. PFRA.040 is supplied in bulk packaging. Packaging selection depends on procurement volume and inventory management requirements.

Q: Are all substitute parts RoHS3 compliant?

A: Yes. All identified substitute parts carry ROHS3 Compliant status, matching the environmental compliance of the original MF-R040-0-99.

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