Equivalent & Substitute Parts for MF-RX185

Part Overview

The Bourns MF-RX185 is a polymeric PTC resettable fuse rated for 60V at 1.85A hold current, designed for through-hole radial mounting in disc configuration. This component is classified as obsolete, making equivalent and substitute parts necessary for ongoing design support and procurement. The MF-RX185 operates across -40°C to 85°C and meets cURus and TUV approval requirements with ROHS3 compliance.

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 is determined by the following critical parameters:

Electrical Parameters (Primary):

Voltage - Max: 60V minimum (higher voltage ratings are acceptable)
Current - Hold (Ih) (Max): 1.85A (exact match required)
Current - Trip (It): 3.7A (exact match required)
Resistance - Initial (Ri) (Min): 80 mOhms (exact match required)
Resistance - Post Trip (R1) (Max): 190 mOhms (exact match required)
Time to Trip: 12.6 s (exact match required)

Mechanical Parameters (Secondary):

Mounting Type: Through Hole (required)
Package / Case: Radial, Disc (required)
Lead Spacing: 0.201" (5.10mm) or compatible spacing

Compliance Parameters:

RoHS Status: ROHS3 Compliant (required)
Approval Agency: cURus and/or TUV (required)

Substitute parts are grouped into three categories: parametric equivalents (identical electrical and mechanical specifications from the same manufacturer), direct equivalents (identical specifications from alternative manufacturers), and similar parts (minor dimensional variations with identical electrical performance).

Parameter Comparison

Manufacturer Part Number	Manufacturer	Voltage - Max	Current - Hold (Ih)	Current - Trip (It)	Resistance - Initial (Ri)	Resistance - Post Trip (R1)	Time to Trip	Operating Temperature	Product Status	Lead Spacing	RoHS Status
MF-RX185	Bourns Inc.	60V	1.85 A	3.7 A	80 mOhms	190 mOhms	12.6 s	-40°C ~ 85°C	Obsolete	0.201" (5.10mm)	ROHS3 Compliant
MF-RX185-005	Bourns Inc.	60V	1.85 A	3.7 A	80 mOhms	190 mOhms	12.6 s	-40°C ~ 85°C	Active	0.201" (5.10mm)	ROHS3 Compliant
MF-RX185/72-0	Bourns Inc.	72V	1.85 A	3.7 A	80 mOhms	190 mOhms	12.6 s	-40°C ~ 85°C	Active	0.201" (5.10mm)	ROHS3 Compliant
MF-RX185/72-0-14	Bourns Inc.	72V	1.85 A	3.7 A	80 mOhms	190 mOhms	12.6 s	-40°C ~ 85°C	Active	0.201" (5.10mm)	ROHS3 Compliant
0ZRC0185FF1A	Bel Fuse Inc.	90V	1.85 A	3.7 A	80 mOhms	190 mOhms	12.6 s	-40°C ~ 85°C	Active	0.201" (5.10mm)	ROHS3 Compliant
60R185XMR	Littelfuse Inc.	60V	1.85 A	3.7 A	80 mOhms	190 mOhms	12.6 s	-40°C ~ 85°C	Active	0.201" (5.10mm)	ROHS3 Compliant
PTR060V0185-TR	Eaton - Electronics Division	60V	1.85 A	3.7 A	80 mOhms	190 mOhms	12.6 s	-40°C ~ 85°C	Active	0.197" (5.00mm)	ROHS3 Compliant
60R185XF	Littelfuse	60V	1.85 A	3.7 A	80 mOhms	190 mOhms	12.6 s	-40°C ~ 85°C	Active	0.201" (5.10mm)	ROHS3 Compliant

Engineering Selection Recommendations

Parametric Equivalent (Recommended Primary Substitute): MF-RX185-005 from Bourns Inc. is the direct parametric equivalent with identical electrical and mechanical specifications. This part carries Active product status and maintains full compatibility with the obsolete MF-RX185 in all circuit applications. Inventory availability is 873 pieces.

Parametric Equivalents with Voltage Derating: MF-RX185/72-0 and MF-RX185/72-0-14 from Bourns Inc. provide identical electrical performance with elevated voltage ratings (72V). These parts are suitable for applications where the 60V specification of the original part is not a limiting constraint. Both carry Active status with substantial inventory (4200 and 16312 pieces respectively).

Direct Equivalents from Alternative Manufacturers: 60R185XMR (Littelfuse Inc.) and PTR060V0185-TR (Eaton - Electronics Division) provide direct electrical equivalence at 60V with Active product status. Both meet cURus and TUV approval requirements and ROHS3 compliance. The Littelfuse part maintains exact lead spacing (0.201"), while the Eaton part has minor lead spacing variation (0.197"). Both are suitable for direct substitution in through-hole applications.

Higher Voltage Alternative: 0ZRC0185FF1A from Bel Fuse Inc. operates at 90V with identical electrical parameters and Active status. This part includes AEC-Q200 rating and is appropriate for applications requiring enhanced voltage margin.

Similar Part (Dimensional Variation): 60R185XF from Littelfuse provides identical electrical specifications with minor dimensional differences in the radial disc package. This part is suitable where package footprint tolerance permits the dimensional variation.

All substitute parts maintain ROHS3 compliance and cURus/TUV certifications required for the original MF-RX185 application.

Frequently Asked Questions (FAQ)

Q: Can MF-RX185-005 be used as a direct replacement for MF-RX185? A: Yes. MF-RX185-005 is a parametric equivalent with identical voltage (60V), hold current (1.85A), trip current (3.7A), resistance characteristics, and operating temperature range. The primary difference is product status: MF-RX185-005 is Active while MF-RX185 is Obsolete. No circuit modifications are required.

Q: What is the difference between MF-RX185/72-0 and MF-RX185/72-0-14? A: Both parts are electrically identical with 72V voltage rating and 1.85A hold current. The primary difference is packaging: MF-RX185/72-0 is supplied in Bulk, while MF-RX185/72-0-14 is also Bulk. Both maintain identical electrical performance and lead spacing (0.201"). Selection depends on procurement quantity requirements and inventory availability.

Q: Can I use 0ZRC0185FF1A (90V) in a 60V circuit? A: Yes. The 0ZRC0185FF1A operates at 90V maximum, which exceeds the 60V requirement of the original MF-RX185. All electrical parameters (hold current, trip current, resistance, time to trip) are identical. The higher voltage rating provides additional safety margin and does not affect circuit operation.

Q: What is the lead spacing difference between PTR060V0185-TR and other substitutes? A: PTR060V0185-TR has lead spacing of 0.197" (5.00mm) compared to the standard 0.201" (5.10mm) of MF-RX185 and most substitutes. This 0.004" difference is minor and typically accommodates standard through-hole PCB pad spacing. Verify PCB layout compatibility before selection.

Q: Are 60R185XF and 60R185XMR interchangeable? A: Both are Littelfuse POLY-FUSE parts with identical electrical specifications (60V, 1.85A hold current). The primary difference is packaging: 60R185XF is supplied in Bulk, while 60R185XMR is supplied in Cut Tape (CT). Electrical performance and lead spacing (0.201") are identical. Selection depends on assembly process requirements.

Q: Do all substitute parts meet the same compliance standards as MF-RX185? A: All listed substitutes maintain ROHS3 compliance and cURus/TUV approval. The 0ZRC0185FF1A from Bel Fuse additionally carries AEC-Q200 rating. All parts are suitable for applications requiring the original compliance certifications.

Q: What inventory levels are available for each substitute? A: MF-RX185-005: 873 pieces; MF-RX185/72-0: 4200 pieces; MF-RX185/72-0-14: 16312 pieces; 0ZRC0185FF1A: 5037 pieces; 60R185XMR: 9136 pieces; PTR060V0185-TR: 691 pieces; 60R185XF: 4463 pieces. Inventory levels support various procurement volumes.

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