Equivalent & Substitute Parts for 06R155BU

Part Overview

The 06R155BU is a polymeric PTC resettable fuse manufactured by Littelfuse Inc., rated for 6V at 1.55A hold current with through-hole radial mounting. This component is classified as obsolete, making identification of active equivalent parts essential for ongoing design support and procurement continuity. The substitute part RUSBF155 provides functional equivalence while maintaining active product status.

Substiute Parts

06R155BU

Littelfuse Inc.In Stock: 122206R155BU Datasheet

Current PartRFQ

RUSBF155

Littelfuse Inc.In Stock: 4950RUSBF155 Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

The RUSBF155 qualifies as a direct substitute for the 06R155BU based on the following criteria:

• Identical voltage rating (6V maximum)
• Identical hold current specification (1.55A maximum)
• Matching current trip specification (2.7A vs 2.65A, within operational tolerance)
• Identical maximum current rating (40A)
• Identical time to trip (2.2s)
• Matching initial and post-trip resistance specifications
• Identical operating temperature range (-40°C to 85°C)
• Identical mounting type and package configuration (through-hole radial disc)
• Identical lead spacing (0.201" / 5.10mm)
• Equivalent RoHS3 compliance

The primary distinction is product status: 06R155BU is obsolete while RUSBF155 maintains active status with higher inventory availability.

Parameter Comparison

Engineering Selection Recommendations

The RUSBF155 is the appropriate selection for applications currently specified with 06R155BU. The substitute maintains electrical and mechanical compatibility across all critical parameters. RUSBF155 offers the additional advantage of active product status, ensuring long-term availability and supply chain continuity. The expanded approval agency certifications (CSA, TUV, UL versus cURus, TUV) provide broader regulatory acceptance. Current inventory levels for RUSBF155 (4,868 pieces) significantly exceed those of the obsolete 06R155BU (1,190 pieces), supporting procurement reliability.

Frequently Asked Questions (FAQ)

Q: Can RUSBF155 be used as a direct replacement for 06R155BU in existing designs?

A: Yes. Both parts share identical electrical ratings (6V, 1.55A hold current), matching resistance specifications, and identical through-hole radial disc packaging with 0.201" lead spacing. PCB layout compatibility is maintained.

Q: What is the significance of the Current - Trip (It) difference between the two parts?

A: The 06R155BU specifies 2.7A trip current while RUSBF155 specifies 2.65A. This 0.05A variance falls within normal manufacturing tolerance for polymeric PTC resettable fuses and does not affect functional equivalence for circuit protection applications.

Q: Are there any thermal or environmental limitations when substituting RUSBF155 for 06R155BU?

A: No. Both parts operate across the identical temperature range of -40°C to 85°C. Environmental performance characteristics remain unchanged.

Q: Does the packaging change from 06R155BU to RUSBF155 affect board assembly?

A: No. Both parts use through-hole radial disc mounting with identical lead spacing (0.201" / 5.10mm). Existing PCB footprints require no modification.

Q: What regulatory certifications apply to RUSBF155?

A: RUSBF155 carries CSA, TUV, and UL approvals. The 06R155BU carried cURus and TUV approvals. RUSBF155 provides broader regulatory acceptance while maintaining RoHS3 compliance.

Q: Why is 06R155BU classified as obsolete?

A: Product status reflects manufacturer lifecycle decisions. RUSBF155 represents the active equivalent within Littelfuse's current product portfolio for this electrical specification class.