Equivalent & Substitute Parts for MF-RX185-0-99

Part Overview

The Bourns MF-RX185-0-99 is a polymeric PTC resettable fuse rated at 60V, 1.85A hold current, designed for through-hole radial mounting in disc configuration. This part is classified as obsolete, making identification of active equivalent and substitute components essential for ongoing design support and procurement continuity. Equivalent parts maintain identical electrical and mechanical specifications, while substitute parts may vary in voltage rating or packaging while preserving core functional parameters.

Key Parameters

Parameter	Value
Voltage - Max	60V
Current - Hold (Ih) (Max)	1.85 A
Current - Trip (It)	3.7 A
Current - Max	40 A
Time to Trip	12.6 s
Resistance - Initial (Ri) (Min)	80 mOhms
Resistance - Post Trip (R1) (Max)	190 mOhms
Operating Temperature	-40°C ~ 85°C
Mounting Type	Through Hole
Package / Case	Radial, Disc
Lead Spacing	0.201" (5.10mm)
Approval Agency	cURus, TUV
RoHS Status	ROHS3 Compliant

Substitute Part Grouping Explanation

Substitution eligibility for the MF-RX185-0-99 is determined by the following critical parameters:

Parametric Equivalents (Identical Electrical & Mechanical Specifications):

Voltage - Max: 60V
Current - Hold (Ih): 1.85 A
Current - Trip (It): 3.7 A
Resistance - Initial (Ri): 80 mOhms minimum
Resistance - Post Trip (R1): 190 mOhms maximum
Operating Temperature: -40°C ~ 85°C
Mounting Type: Through Hole
Package / Case: Radial, Disc
Lead Spacing: 0.201" (5.10mm)

Voltage-Rated Variants (Higher Voltage Rating, Identical Current & Thermal Characteristics):

Voltage - Max: 72V (higher rating, backward compatible in 60V applications)
All other electrical and mechanical parameters remain identical

Cross-Manufacturer Equivalents (Different Manufacturer, Identical Specifications):

Voltage - Max: 60V
Current - Hold (Ih): 1.85 A
All electrical and mechanical parameters match the original part

Parameter Comparison

Parameter	MF-RX185-0-99 (Main)	MF-RX185-005	MF-RX185/72-0	MF-RX185/72-0-14	60R185XF
Manufacturer	Bourns Inc.	Bourns Inc.	Bourns Inc.	Bourns Inc.	Littelfuse
Product Status	Obsolete	Active	Active	Active	Active
Voltage - Max	60V	60V	72V	72V	60V
Current - Hold (Ih) (Max)	1.85 A	1.85 A	1.85 A	1.85 A	1.85 A
Current - Trip (It)	3.7 A	3.7 A	3.7 A	3.7 A	3.7 A
Current - Max	40 A	40 A	40 A	40 A	40 A
Time to Trip	12.6 s	12.6 s	12.6 s	12.6 s	12.6 s
Resistance - Initial (Ri) (Min)	80 mOhms	80 mOhms	80 mOhms	80 mOhms	80 mOhms
Resistance - Post Trip (R1) (Max)	190 mOhms	190 mOhms	190 mOhms	190 mOhms	190 mOhms
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
Lead Spacing	0.201" (5.10mm)	0.201" (5.10mm)	0.201" (5.10mm)	0.201" (5.10mm)	0.201" (5.10mm)
Approval Agency	cURus, TUV	cURus, TUV	cURus, TUV	cURus, TUV	cURus, TUV
RoHS Status	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant
Inventory Status	887 Pcs	873 Pcs	4200 Pcs	16312 Pcs	4463 Pcs

Engineering Selection Recommendations

Direct Parametric Equivalent (Preferred for Obsolete Part Replacement): MF-RX185-005 is the active equivalent from Bourns Inc., maintaining identical electrical specifications, thermal characteristics, and mechanical form factor. This part is recommended as the primary replacement for the obsolete MF-RX185-0-99 due to product status transition from obsolete to active while preserving all functional parameters.

Voltage-Rated Variants (Higher Voltage Tolerance): MF-RX185/72-0 and MF-RX185/72-0-14 are rated at 72V maximum voltage with identical current-hold and trip characteristics. These parts are suitable for applications where the original 60V rating provides adequate margin, as the higher voltage rating does not compromise performance in 60V circuits. Both parts maintain ROHS3 compliance and cURus/TUV certifications. MF-RX185/72-0-14 offers significantly higher inventory availability (16312 Pcs).

Cross-Manufacturer Equivalent (Alternative Source): 60R185XF from Littelfuse is a direct electrical and mechanical equivalent rated at 60V, 1.85A hold current. This part provides supply chain diversification while maintaining identical functional specifications, thermal performance, and regulatory compliance (ROHS3, cURus, TUV). Physical dimensions vary slightly (0.660" Dia vs. 0.701" L), though lead spacing and mounting type remain identical.

Frequently Asked Questions (FAQ)

Q: Can MF-RX185-005 be used as a direct replacement for the obsolete MF-RX185-0-99? A: Yes. MF-RX185-005 is a parametric equivalent with identical voltage (60V), current-hold (1.85A), current-trip (3.7A), resistance characteristics, operating temperature range, and mechanical form factor. The primary difference is product status transition from obsolete to active.

Q: What is the difference between the 60V and 72V rated variants? A: The 72V variants (MF-RX185/72-0 and MF-RX185/72-0-14) have a higher maximum voltage rating but identical current-hold, current-trip, and thermal characteristics. These parts are suitable for 60V applications and provide additional voltage margin. Selection depends on circuit requirements and inventory availability.

Q: Are there mechanical differences between Bourns and Littelfuse parts? A: The 60R185XF from Littelfuse has a slightly different physical dimension (0.660" Dia vs. 0.701" L for the Bourns part), but maintains identical lead spacing (0.201" / 5.10mm) and through-hole radial disc mounting configuration. PCB layout compatibility should be verified based on specific footprint requirements.

Q: Do all substitute parts maintain the same regulatory compliance? A: Yes. All listed substitute parts are ROHS3 compliant and carry cURus and TUV approvals, matching the original part's regulatory status.

Q: Which part should be selected for new designs? A: MF-RX185-005 is recommended for designs requiring the original 60V specification. MF-RX185/72-0-14 offers the highest inventory availability if voltage margin is acceptable. 60R185XF provides cross-manufacturer sourcing flexibility.

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