MF-R075-0-99 Polymeric PTC Resettable Fuse Equivalent & Substitute Parts

Part Overview

The Bourns MF-R075-0-99 is a polymeric PTC resettable fuse rated for 60V maximum voltage with 750 mA hold current. This component is classified as obsolete, necessitating identification of active equivalent and substitute parts for ongoing circuit protection applications. The part operates through thermal response to overcurrent conditions, automatically resetting when the fault is cleared. Equivalent parts maintain identical electrical performance characteristics while substitute parts offer compatible operation within specified parameter ranges.

Key Parameters

Parameter	Value
Voltage - Max	60V
Current - Hold (Ih) (Max)	750 mA
Current - Trip (It)	1.5 A
Current - Max	40 A
Time to Trip	6.3 s
Resistance - Initial (Ri) (Min)	180 mOhms
Resistance - Post Trip (R1) (Max)	600 mOhms
Operating Temperature	-40°C ~ 85°C
Mounting Type	Through Hole
Package / Case	Radial, Disc
Size / Dimension	0.409" Dia x 0.122" T (10.40mm x 3.10mm)
Lead Spacing	0.201" (5.10mm)
RoHS Status	ROHS3 Compliant

Substitute Part Grouping Explanation

Substitution validity is determined by strict alignment of electrical parameters: maximum voltage rating, hold current (Ih), trip current (It), maximum current capacity, time to trip, and resistance characteristics. Mechanical compatibility requires identical mounting type (through hole), package form (radial disc), and lead spacing (0.201" / 5.10mm). All substitute parts listed maintain these core parameters within the specified ranges.

Bourns Multifuse® MF-R series parts with 60V/750mA ratings are parametric equivalents. The MF-RX075/72-0 series operates at 72V maximum voltage, which is compatible for 60V circuit applications due to higher voltage margin. Littelfuse PolySwitch® RXEF075 and POLY-FUSE® 60R075XU maintain identical electrical performance with minor dimensional variations within acceptable tolerances. SCHURTER PFRA.075 provides parametric equivalence at 60V/750mA with identical mechanical form factor.

Parameter Comparison

Part Number	Manufacturer	Voltage - Max	Current - Hold (Ih)	Current - Trip (It)	Resistance - Initial (Ri)	Resistance - Post Trip (R1)	Product Status	Approval Agency
MF-R075-0-99	Bourns Inc.	60V	750 mA	1.5 A	180 mOhms	600 mOhms	Obsolete	cURus, TUV
MF-R075	Bourns Inc.	60V	750 mA	1.5 A	180 mOhms	600 mOhms	Active	cURus, TUV
MF-R075-0-17	Bourns Inc.	60V	750 mA	1.5 A	180 mOhms	600 mOhms	Active	cUL, cURus, TUV, UL
MF-R075-0-A0	Bourns Inc.	60V	750 mA	1.5 A	180 mOhms	600 mOhms	Active	cURus, TUV
MF-RX075/72-0	Bourns Inc.	72V	750 mA	1.5 A	180 mOhms	600 mOhms	Active	cURus, TUV
MF-RX075/72-0-17	Bourns Inc.	72V	750 mA	1.5 A	180 mOhms	600 mOhms	Active	cUL, cURus, TUV, UL
RXEF075	Littelfuse Inc.	72V	750 mA	1.5 A	250 mOhms	600 mOhms	Active	CQC, CSA, TUV, UL
60R075XU	Littelfuse Inc.	60V	750 mA	1.5 A	250 mOhms	600 mOhms	Active	cURus, TUV
PFRA.075	SCHURTER Inc.	60V	750 mA	1.5 A	180 mOhms	600 mOhms	Active	cURus, TUV

Engineering Selection Recommendations

For direct replacement of the obsolete MF-R075-0-99, select from active Bourns Multifuse® MF-R series parts: MF-R075, MF-R075-0-17, or MF-R075-0-A0. These maintain identical electrical and mechanical specifications with active product status and equivalent certifications.

MF-R075-0-17 provides enhanced compliance with cUL and UL approvals in addition to cURus and TUV certifications, suitable for applications requiring broader regulatory acceptance. MF-R075 and MF-R075-0-A0 maintain baseline cURus and TUV approvals matching the original part.

For applications operating below 60V, Bourns MF-RX075/72-0 series (60V and 72V variants) and Littelfuse 60R075XU provide parametric equivalence with active status. The 72V-rated variants offer additional voltage margin for circuits with transient overvoltage conditions.

Littelfuse RXEF075 operates at 72V with identical current and trip characteristics, certified by CQC, CSA, TUV, and UL. Initial resistance is specified at 250 mOhms versus 180 mOhms for Bourns parts; this higher initial resistance remains within acceptable operating parameters for the 750 mA hold current rating.

SCHURTER PFRA.075 provides parametric equivalence at 60V/750mA with identical mechanical form factor and 180 mOhms initial resistance, certified by cURus and TUV.

Frequently Asked Questions (FAQ)

Q: Can MF-RX075/72-0 (72V rated) replace MF-R075-0-99 (60V rated) in a 60V circuit?

A: Yes. The 72V rating provides higher voltage margin than required for 60V operation. All other electrical parameters—hold current, trip current, time to trip, and resistance characteristics—are identical. The higher voltage rating does not degrade performance in lower-voltage applications.

Q: What is the difference between MF-R075, MF-R075-0-17, and MF-R075-0-A0?

A: All three maintain identical electrical specifications (60V, 750 mA hold current, 1.5 A trip current). MF-R075-0-17 includes additional cUL and UL certifications. MF-R075 and MF-R075-0-A0 carry cURus and TUV approvals. Selection depends on required regulatory certifications for the application.

Q: Why does RXEF075 specify 250 mOhms initial resistance while Bourns parts specify 180 mOhms?

A: Both values fall within acceptable operating ranges for the 750 mA hold current specification. The higher initial resistance of the Littelfuse part results in slightly higher voltage drop during normal operation but maintains identical trip current and thermal response characteristics.

Q: Are all substitute parts mechanically compatible with the original MF-R075-0-99 footprint?

A: Yes. All listed parts maintain through-hole radial disc mounting with 0.201" (5.10mm) lead spacing. Dimensional variations in diameter and thickness are within acceptable PCB assembly tolerances.

Q: Which substitute part has the broadest regulatory approval?

A: MF-R075-0-17 and RXEF075 both carry four regulatory approvals. MF-R075-0-17 is certified by cUL, cURus, TUV, and UL. RXEF075 is certified by CQC, CSA, TUV, and UL. Selection depends on specific regional requirements.

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