RUSB110 Polymeric PTC Resettable Fuse Equivalent & Substitute Parts

Part Overview

The RUSB110 is a polymeric PTC (Positive Temperature Coefficient) resettable fuse manufactured by Littelfuse, rated for 16V at 1.1A hold current. This component functions as an automatic reset protection device for circuit overcurrent conditions. The RUSB110 is classified as obsolete, making identification of active equivalent parts essential for ongoing design support, maintenance, and new production sourcing. Active substitute parts maintain identical electrical and mechanical specifications while offering current manufacturing availability and updated compliance certifications.

Substiute Parts

RUSB110

LittelfuseIn Stock: 1014RUSB110 Datasheet

Current PartRFQ

RUSBF110

LittelfuseIn Stock: 952RUSBF110 Datasheet

DirectRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the RUSB110 is determined by strict equivalence across electrical and mechanical parameters. The following criteria establish direct substitutability:

• Voltage rating of 16V maximum
• Hold current (Ih) of 1.1A
• Trip current (It) of 2.2A
• Maximum current capacity of 40A
• Trip time of 2.3 seconds
• Initial resistance of 50 mOhms minimum
• Post-trip resistance of 140 mOhms maximum
• Through-hole radial disc package configuration
• Lead spacing of 0.199" (5.05mm)
• PolySwitch® series designation

The RUSBF110 meets all specified electrical and mechanical parameters, establishing it as a direct functional equivalent. The primary distinction is product status: RUSB110 is obsolete, while RUSBF110 is active production.

Parameter Comparison

Engineering Selection Recommendations

The RUSBF110 is the direct active equivalent for RUSB110 applications. Selection of RUSBF110 is supported by:

• Identical electrical performance across all specified parameters
• Identical mechanical form factor and lead spacing for direct PCB compatibility
• Active production status ensuring supply chain availability
• ROHS3 compliance, addressing modern regulatory requirements
• Updated approval certifications (UL replaces UR designation)
• Maintained PolySwitch® series heritage with RUSBF designation

For applications requiring the RUSB110, transition to RUSBF110 provides equivalent circuit protection without design modification or PCB rework.

Frequently Asked Questions (FAQ)

Q: Can RUSBF110 be used as a direct replacement for RUSB110 in existing designs?

A: Yes. RUSBF110 maintains identical electrical specifications (16V, 1.1A hold current, 2.2A trip current, 2.3s trip time) and mechanical dimensions (radial disc package, 5.05mm lead spacing). No circuit redesign or PCB modification is required.

Q: What is the primary difference between RUSB110 and RUSBF110?

A: RUSB110 is obsolete; RUSBF110 is active production. RUSBF110 also carries ROHS3 compliance and updated regulatory certifications (UL vs. UR).

Q: Are the physical dimensions identical between these parts?

A: Yes. Both parts measure 7.40mm x 3.00mm with a maximum seated height of 14.20mm and lead spacing of 5.05mm. They are mechanically interchangeable.

Q: Does RUSBF110 provide the same overcurrent protection characteristics?

A: Yes. Hold current (Ih), trip current (It), trip time, and resistance specifications are identical. Protection behavior in circuit is equivalent.

Q: What packaging is available for RUSBF110?

A: RUSBF110 is supplied in bag packaging, compared to the dash (-) packaging designation for RUSB110.