Equivalent & Substitute Parts for MF-R040-AP-99

Part Overview

The MF-R040-AP-99 is a Polymeric PTC Resettable Fuse manufactured by Bourns Inc. as part of the Multifuse® MF-R series. This component is rated for 60V maximum voltage with a 400 mA hold current and is designed for through-hole radial mounting in disc configuration. The part is currently listed as obsolete, making identification of active equivalent alternatives essential 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 for the MF-R040-AP-99 is determined by strict equivalence across the following critical parameters:

Voltage rating: 60V maximum
Hold current (Ih): 400 mA maximum
Trip current (It): 800 mA
Time to trip: 3.8 seconds
Initial resistance (Ri): 520 mOhms minimum
Post-trip resistance (R1): 1.29 Ohms maximum
Mounting configuration: Through-hole radial disc
Physical dimensions: 0.291" diameter × 0.122" thickness (7.40mm × 3.10mm)
Lead spacing: 0.201" (5.10mm)

All identified substitutes maintain identical electrical and mechanical specifications, ensuring direct functional replacement in circuit applications.

Parameter Comparison

Parameter	MF-R040-AP-99	MF-R040-AP	MF-R040-AP-17
Manufacturer	Bourns Inc.	Bourns Inc.	Bourns Inc.
Series	Multifuse® MF-R	Multifuse® MF-R	Multifuse® MF-R
Type	Polymeric	Polymeric	Polymeric
Voltage - Max	60V	60V	60V
Current - Hold (Ih) (Max)	400 mA	400 mA	400 mA
Current - Trip (It)	800 mA	800 mA	800 mA
Current - Max	40 A	40 A	40 A
Time to Trip	3.8 s	3.8 s	3.8 s
Resistance - Initial (Ri) (Min)	520 mOhms	520 mOhms	520 mOhms
Resistance - Post Trip (R1) (Max)	1.29 Ohms	1.29 Ohms	1.29 Ohms
Operating Temperature	-40°C ~ 85°C	-40°C ~ 85°C	-40°C ~ 85°C
Mounting Type	Through Hole	Through Hole	Through Hole
Package / Case	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)
Lead Spacing	0.201" (5.10mm)	0.201" (5.10mm)	0.201" (5.10mm)
Product Status	Obsolete	Active	Active
Packaging	-	Tape & Box (TB)	Tape & Box (TB)
RoHS Status	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant
Approval Agency	cURus, TUV	cURus, TUV	cUL, cURus, TUV, UL

Engineering Selection Recommendations

Both MF-R040-AP and MF-R040-AP-17 are active product alternatives to the obsolete MF-R040-AP-99. Selection between these substitutes should be based on the following factors:

MF-R040-AP maintains the same certification profile as the original part (cURus, TUV) and is suitable for applications where the original certifications are sufficient.

MF-R040-AP-17 provides extended regulatory coverage with additional certifications (cUL, UL) and includes AEC-Q200 automotive qualification rating. This variant is appropriate for applications requiring automotive-grade reliability or broader regulatory compliance.

Both parts are ROHS3 compliant, REACH unaffected, and available in Tape & Box packaging. Electrical and mechanical parameters are identical across all three part numbers, ensuring direct circuit compatibility.

Frequently Asked Questions (FAQ)

Q: Can MF-R040-AP or MF-R040-AP-17 be used as direct replacements for MF-R040-AP-99?

A: Yes. All three parts share identical electrical specifications (60V, 400 mA hold current, 800 mA trip current, 3.8 s trip time) and mechanical dimensions (0.291" diameter × 0.122" thickness, 0.201" lead spacing). The MF-R040-AP-99 is obsolete; MF-R040-AP and MF-R040-AP-17 are active alternatives.

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

A: The primary difference is regulatory certification. MF-R040-AP carries cURus and TUV approvals. MF-R040-AP-17 includes additional certifications (cUL, UL) and AEC-Q200 automotive qualification. Electrical and mechanical specifications are identical.

Q: Which substitute should I select for automotive applications?

A: MF-R040-AP-17 is qualified to AEC-Q200 automotive standards and carries UL and cUL certifications in addition to cURus and TUV. This part is the appropriate choice for automotive circuit protection requirements.

Q: Are there packaging differences between the substitutes?

A: The original MF-R040-AP-99 packaging is not specified. Both active alternatives (MF-R040-AP and MF-R040-AP-17) are supplied in Tape & Box (TB) packaging, which is standard for through-hole component distribution.

Q: Do all three parts meet RoHS compliance?

A: Yes. MF-R040-AP-99, MF-R040-AP, and MF-R040-AP-17 are all ROHS3 compliant and REACH unaffected.

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