PFRX.185.3 Equivalent & Substitute Parts

Part Overview

The PFRX.185.3 is a polymeric PTC resettable fuse manufactured by SCHURTER Inc., rated for 60V maximum voltage with a 1.85A hold current. This component is classified as obsolete, making equivalent substitute parts necessary for ongoing system maintenance and new design implementations. The PFRX series has been superseded by active alternatives that maintain electrical compatibility while offering improved availability and extended product lifecycle support.

Substiute Parts

PFRX.185.3

SCHURTER Inc.In Stock: 994PFRX.185.3 Datasheet

Current PartRFQ

PFRY.185

SCHURTER Inc.In Stock: 2978PFRY.185 Datasheet

DirectRFQ

RXEF185-AP

Littelfuse Inc.In Stock: 1185RXEF185-AP Datasheet

DirectRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the PFRX.185.3 is determined by the following critical parameters:

Electrical Compatibility Requirements:

• Current - Hold (Ih) (Max): Must equal 1.85 A
• Current - Trip (It): Must equal 3.7 A
• Resistance - Initial (Ri) (Min): Must equal 80 mOhms
• Resistance - Post Trip (R1) (Max): Must equal 190 mOhms
• Time to Trip: Must equal 12.6 s
• Operating Temperature: Must support -40°C ~ 85°C range

Mechanical Compatibility Requirements:

• Mounting Type: Through Hole
• Package / Case: Radial, Disc
• Lead Spacing: 0.201" (5.10mm)

Voltage Consideration: Substitute parts rated at 72V maximum voltage are acceptable for applications originally designed for 60V operation, as the higher voltage rating provides enhanced safety margin and maintains all other electrical characteristics.

Two substitute parts meet these criteria: PFRY.185 (SCHURTER Inc.) and RXEF185-AP (Littelfuse Inc., PolySwitch® series).

Parameter Comparison

Engineering Selection Recommendations

PFRY.185 (SCHURTER Inc.): This substitute maintains manufacturer continuity with the original PFRX.185.3, both sourced from SCHURTER Inc. The PFRY.185 is active in production with higher inventory availability (2,908 pcs). It carries TUV and cURus certifications. The 72V voltage rating provides enhanced margin over the original 60V specification. Lead spacing remains identical at 0.201" (5.10mm), ensuring direct mechanical compatibility. This option is suitable for applications prioritizing supply chain consistency within the same manufacturer ecosystem.

RXEF185-AP (Littelfuse Inc., PolySwitch® series): This substitute is the Littelfuse equivalent, featuring the PolySwitch® branded polymeric PTC technology. The RXEF185-AP holds active product status with 1,089 pcs in stock. It provides the broadest certification coverage (CQC, CSA, TUV, UL), exceeding the original part's certifications. The 72V voltage rating matches the PFRY.185. Lead spacing is 0.199" (5.05mm), a 0.002" (0.05mm) variance from the original specification, which remains within standard PCB tolerance for radial component placement. This option is suitable for applications requiring multi-source qualification or where Littelfuse PolySwitch® components are already established in the design.

Both substitutes satisfy all critical electrical parameters and maintain full compliance with RoHS3 and REACH requirements.

Frequently Asked Questions (FAQ)

Q: Can PFRY.185 or RXEF185-AP be used as direct replacements for PFRX.185.3?

A: Yes. Both substitutes maintain identical hold current (1.85A), trip current (3.7A), initial resistance (80 mOhms), post-trip resistance (190 mOhms), and time to trip (12.6s) specifications. The 72V voltage rating of both substitutes exceeds the original 60V requirement, providing enhanced safety margin. All three components share Through Hole, Radial Disc packaging with compatible lead spacing.

Q: What is the difference in lead spacing between the parts?

A: PFRX.185.3 and PFRY.185 both specify 0.201" (5.10mm) lead spacing. RXEF185-AP specifies 0.199" (5.05mm), a 0.002" (0.05mm) difference. This variance is within standard PCB design tolerances for radial component placement and does not affect functional compatibility.

Q: Why do the substitute parts have higher voltage ratings (72V vs. 60V)?

A: The 72V rating represents the maximum voltage specification for these substitute products. Using a component with a higher voltage rating in a 60V application is standard engineering practice and provides additional safety margin without affecting performance at the lower voltage.

Q: Are there compliance or certification differences between the substitutes?

A: PFRX.185.3 carries CSA, TUV, and UL certifications. PFRY.185 carries cURus and TUV certifications. RXEF185-AP carries CQC, CSA, TUV, and UL certifications. All three meet RoHS3 and REACH compliance requirements. Application-specific certification requirements should be verified against your system's regulatory needs.

Q: What is the difference between SCHURTER and Littelfuse polymeric PTC fuses?

A: Both manufacturers produce polymeric PTC resettable fuses with identical electrical characteristics for this specification. SCHURTER (PFRY.185) and Littelfuse (RXEF185-AP, PolySwitch® series) are established suppliers in this component category. Selection between them depends on existing supply chain relationships, certification requirements, and inventory availability.

Q: Is the PFRX.185.3 still available?

A: The PFRX.185.3 is classified as obsolete. Current inventory of 976 pcs is available, but long-term supply cannot be guaranteed. PFRY.185 (2,908 pcs) and RXEF185-AP (1,089 pcs) are both active products with established supply chains.