RUSB075 Polymeric PTC Resettable Fuse Equivalent & Substitute Parts

Part Overview

The RUSB075 is a polymeric PTC (Positive Temperature Coefficient) resettable fuse manufactured by Littelfuse Inc. in the PolySwitch® series. This component provides overcurrent protection with automatic reset capability in a through-hole radial disc package rated for 6V and 750 mA hold current.

The RUSB075 is classified as obsolete. Identifying equivalent and substitute parts is necessary to maintain design continuity, ensure supply chain availability, and support ongoing production or repair requirements for systems utilizing this component.

Substiute Parts

RUSB075

Littelfuse Inc.In Stock: 1024RUSB075 Datasheet

Current PartRFQ

RUSBF075

LittelfuseIn Stock: 3724RUSBF075 Datasheet

DirectRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the RUSB075 is determined by strict equivalence across the following critical parameters:

• Voltage rating: 6V maximum
• Current hold specification: 750 mA
• Current trip specification: 1.3 A
• Time to trip: 400 ms
• Initial resistance: 110 mOhms minimum
• Post-trip resistance: 230 mOhms maximum
• Mounting configuration: Through hole radial disc
• Lead spacing: 0.201" (5.10mm)
• Package type: Radial, Disc

The RUSBF075 meets all these criteria and is classified as a direct substitute. Both components share identical electrical performance specifications and mechanical compatibility within the specified tolerance ranges.

Parameter Comparison

Engineering Selection Recommendations

The RUSBF075 is the direct substitute for the obsolete RUSB075. Both components are manufactured by Littelfuse and share identical electrical and mechanical specifications across all critical parameters.

The RUSBF075 offers the following advantages:

• Active product status ensures ongoing availability and supply chain support
• ROHS3 compliance meets current environmental and regulatory requirements
• Documented operating temperature range of -40°C to 85°C provides explicit thermal performance specification
• Expanded approval certifications (CSA, TUV, UL) compared to the original part
• Identical lead spacing and package dimensions ensure direct PCB compatibility

For applications requiring the RUSB075, the RUSBF075 provides equivalent electrical performance and mechanical fit with improved compliance and availability status.

Frequently Asked Questions (FAQ)

Q: Can the RUSBF075 be used as a direct replacement for the RUSB075?

A: Yes. The RUSBF075 meets all electrical and mechanical specifications of the RUSB075, including voltage rating, current hold and trip values, resistance characteristics, and package dimensions. Both components are through-hole radial disc packages with identical lead spacing.

Q: What is the difference between the RUSB075 and RUSBF075?

A: The primary differences are product status and compliance. The RUSB075 is obsolete, while the RUSBF075 is active. The RUSBF075 is ROHS3 compliant and includes an explicit operating temperature range specification (-40°C to 85°C). Electrical performance and mechanical dimensions are equivalent.

Q: Are there any dimensional differences that would affect PCB compatibility?

A: Dimensional differences are minimal. The RUSB075 is specified as 0.272" L x 0.118" W, while the RUSBF075 is 0.272" Dia x 0.122" T. Both maintain the same 0.201" (5.10mm) lead spacing and 0.449" (11.40mm) seated height. These variations fall within standard PCB layout tolerances for through-hole radial components.

Q: Does the RUSBF075 have the same approval certifications?

A: The RUSBF075 carries CSA, TUV, and UL certifications, compared to CSA, TUV, and UR for the RUSB075. Both meet industry safety standards for polymeric PTC resettable fuses in this voltage and current class.

Q: Is the RUSBF075 RoHS compliant?

A: Yes. The RUSBF075 is ROHS3 compliant, whereas the RUSB075 is RoHS non-compliant. This makes the RUSBF075 suitable for applications subject to RoHS regulations.