RUSB185 Equivalent & Substitute Parts

Part Overview

The RUSB185 is a polymeric PTC resettable fuse manufactured by Littelfuse Inc. in the PolySwitch® series, rated for 16V and 1.85A hold current. This component is designed for overcurrent protection in electronic circuits through a radial, disc-mounted through-hole package. The RUSB185 is currently listed as obsolete, making identification of compatible substitute parts essential for ongoing system support and new design implementations.

Substiute Parts

RUSB185

Littelfuse Inc.In Stock: 725RUSB185 Datasheet

Current PartRFQ

RUSBF185

Littelfuse Inc.In Stock: 1197RUSBF185 Datasheet

DirectRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the RUSB185 is determined by strict equivalence across the following critical parameters:

• Voltage rating: 16V maximum
• Current hold specification: 1.85A
• Current trip specification: 3.7A
• Mounting configuration: Through hole radial disc package
• Lead spacing: 0.199" (5.05mm)
• Resistance characteristics: Initial minimum 30 mOhms, post-trip maximum 90 mOhms
• Time to trip: 10 seconds

The RUSBF185 meets all these electrical and mechanical requirements, providing direct functional equivalence to the obsolete RUSB185.

Parameter Comparison

Engineering Selection Recommendations

The RUSBF185 is the direct substitute for the obsolete RUSB185. Both components share identical electrical specifications and mechanical form factors, ensuring pin-compatible replacement without circuit modification.

The RUSBF185 offers the additional advantage of active product status and ROHS3 compliance, making it suitable for new designs and systems requiring environmental regulatory adherence. The RUSBF185 maintains all functional protection characteristics of the original RUSB185 while providing improved availability and compliance posture.

Frequently Asked Questions (FAQ)

Q: Can RUSBF185 be used as a direct replacement for RUSB185? A: Yes. The RUSBF185 provides electrical and mechanical equivalence across all specified parameters, including voltage rating, current hold and trip specifications, resistance characteristics, and through-hole radial disc package configuration.

Q: Are there differences in approval certifications between RUSB185 and RUSBF185? A: The RUSB185 carries CSA, TUV, and UR approvals. The RUSBF185 carries CSA, TUV, and UL approvals. Both meet industry safety standards appropriate for overcurrent protection applications.

Q: What is the significance of RoHS compliance difference? A: The RUSB185 is RoHS non-compliant, while RUSBF185 is ROHS3 compliant. For applications subject to environmental regulations or customer requirements mandating RoHS compliance, the RUSBF185 is the appropriate selection.

Q: Will the RUSBF185 function identically in existing RUSB185 circuit designs? A: Yes. Identical electrical characteristics—voltage rating, current hold, current trip, resistance values, and time to trip—ensure functional equivalence in all circuit applications designed for the RUSB185.

Q: Are there packaging differences between these parts? A: The RUSB185 is supplied in standard packaging, while RUSBF185 is supplied in bag packaging. Both maintain identical component dimensions and lead spacing for PCB mounting compatibility.