RUSBF160 Polymeric PTC Resettable Fuse Equivalent & Substitute Parts

Part Overview

The RUSBF160 is an active polymeric PTC resettable fuse manufactured by Littelfuse in the PolySwitch® series. This component provides overcurrent protection with automatic reset capability in through-hole radial configuration. The part is ROHS3 compliant and carries CSA, TUV, and UL approvals. Equivalent and substitute parts are identified based on matching electrical performance parameters, mechanical compatibility, and regulatory certifications to support component sourcing flexibility and supply chain continuity.

Substiute Parts

RUSBF160

LittelfuseIn Stock: 1143RUSBF160 Datasheet

Current PartRFQ

MF-R160

Bourns Inc.In Stock: 8491MF-R160 Datasheet

SimilarRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitute parts for the RUSBF160 are identified based on the following electrical and mechanical criteria:

Matching Parameters:

• Current - Hold (Ih) (Max): 1.6 A
• Current - Trip (It): 3.2 A
• Current - Max: 40 A
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Through Hole
• Package / Case: Radial, Disc
• Lead Spacing: Approximately 0.199" to 0.201" (5.05mm to 5.10mm)
• RoHS Status: ROHS3 Compliant

Allowable Variation:

• Voltage - Max: Substitute parts may exceed the 16V rating, provided the application circuit voltage does not exceed 16V
• Resistance - Initial (Ri) and Resistance - Post Trip (R1): Minor variations within typical manufacturing tolerances are acceptable
• Time to Trip: Variations within ±1 second are acceptable for equivalent functionality
• Approval Agencies: Substitute parts must carry equivalent regulatory certifications (CSA, TUV, cURus)

Parameter Comparison

Engineering Selection Recommendations

The MF-R160 (Bourns Inc.) is a qualified substitute for the RUSBF160 (Littelfuse) based on the following criteria:

Electrical Compatibility: Both parts share identical hold current (1.6 A), trip current (3.2 A), and maximum current (40 A) ratings. The MF-R160 features a higher maximum voltage rating (30V vs. 16V), which provides additional design margin for applications operating at or below 16V. Both parts operate across the same temperature range (-40°C ~ 85°C).

Mechanical Compatibility: Both parts are through-hole mounted in radial disc configuration with lead spacing within 0.06mm tolerance (5.05mm vs. 5.10mm), ensuring PCB footprint compatibility.

Regulatory Compliance: Both parts are ROHS3 compliant and carry TUV certification. The RUSBF160 includes CSA and UL approvals, while the MF-R160 carries cURus certification. Selection should be based on specific regulatory requirements of the end application.

Performance Considerations: The MF-R160 exhibits slightly higher initial resistance (55 mOhms vs. 30 mOhms) and post-trip resistance (150 mOhms vs. 110 mOhms), with a marginally faster trip time (8 s vs. 9 s). These differences fall within acceptable engineering tolerances for equivalent functionality.

Frequently Asked Questions (FAQ)

Q: Can the MF-R160 be used as a direct replacement for the RUSBF160?

A: Yes, the MF-R160 is electrically and mechanically compatible with the RUSBF160 for applications operating at 16V or below. Both parts share identical hold and trip current ratings, operating temperature range, and through-hole radial mounting configuration. Verify that your application's regulatory certification requirements are satisfied by the MF-R160's approval agencies (cURus, TUV).

Q: What is the significance of the voltage rating difference (16V vs. 30V)?

A: The MF-R160's higher voltage rating (30V) does not affect its suitability for 16V applications. The voltage rating indicates the maximum voltage the component can safely withstand. For circuits operating at 16V or below, the 30V-rated MF-R160 provides equivalent protection with additional design margin.

Q: Are there differences in resistance that affect circuit performance?

A: The MF-R160 has higher initial resistance (55 mOhms vs. 30 mOhms) and post-trip resistance (150 mOhms vs. 110 mOhms). In low-impedance circuits where voltage drop across the fuse is critical, these differences may require circuit analysis. For most protection applications, these resistance variations are within acceptable engineering tolerances.

Q: Do the approval agencies differ between these parts?

A: Yes. The RUSBF160 carries CSA, TUV, and UL approvals. The MF-R160 carries cURus and TUV approvals. Select the part whose certifications align with your application's regulatory requirements. TUV certification is common to both.

Q: Is the lead spacing difference (5.05mm vs. 5.10mm) a concern for PCB compatibility?

A: No. The 0.05mm difference in lead spacing is negligible and falls within standard PCB manufacturing tolerances. Both parts are compatible with the same through-hole radial footprint.

Q: What is the difference in time to trip between these parts?

A: The MF-R160 trips in 8 seconds compared to 9 seconds for the RUSBF160. This 1-second difference is within acceptable engineering tolerance for polymeric PTC resettable fuses and does not affect functional equivalence for overcurrent protection applications.