RUSBF135-2 Equivalent & Substitute Parts

Part Overview

The RUSBF135-2 is a polymeric PTC resettable fuse manufactured by Littelfuse, part of the PolySwitch® series. This through-hole radial disc component provides overcurrent protection at 16V with a 1.35A hold current rating. The part is currently active in production with 3207 units in stock. Substitute parts are identified when equivalent electrical and mechanical parameters are required for circuit protection applications where the original part number may be unavailable or when alternative packaging configurations are needed.

Substiute Parts

RUSBF135-2

LittelfuseIn Stock: 3306RUSBF135-2 Datasheet

Current PartRFQ

RUSBF135-AP

LittelfuseIn Stock: 2240RUSBF135-AP Datasheet

Parametric EquivalentRFQ

Key Parameters

Substitute Part Grouping Explanation

The RUSBF135-AP is identified as a parametric equivalent to the RUSBF135-2. Substitution is valid based on the following criteria:

All electrical parameters are identical: 16V maximum voltage, 1.35A hold current, 2.7A trip current, 40A maximum current, and 4.5s time to trip specification. Resistance characteristics match exactly: 40 mOhms minimum initial resistance and 112 mOhms maximum post-trip resistance. Operating temperature range is identical at -40°C to 85°C.

Mechanical compatibility is confirmed: both parts use through-hole mounting with radial disc package configuration, identical physical dimensions of 0.350" L x 0.118" W (8.90mm x 3.00mm), and matching lead spacing of 0.199" (5.05mm).

Compliance and certification are equivalent: both parts carry ROHS3 compliance and are approved by CSA, TUV, and UL agencies. Both are active production parts from Littelfuse's PolySwitch® RUSBF series.

Parameter Comparison

Engineering Selection Recommendations

Both RUSBF135-2 and RUSBF135-AP are suitable for direct substitution in applications requiring 16V polymeric PTC resettable fuse protection with 1.35A hold current specifications. Selection between these parts may be based on inventory availability: RUSBF135-2 has 3207 units in stock, while RUSBF135-AP has 2202 units available. Both parts maintain identical compliance certifications (CSA, TUV, UL) and ROHS3 compliance status, ensuring regulatory requirements are met in either configuration. Both are active production components from Littelfuse, confirming long-term availability and supply chain stability.

Frequently Asked Questions (FAQ)

Q: Can RUSBF135-AP be used as a direct replacement for RUSBF135-2?

A: Yes. All electrical parameters, mechanical dimensions, lead spacing, and compliance certifications are identical between the two parts. Direct substitution is valid for through-hole radial disc mounting applications.

Q: What are the key parameters that determine substitution eligibility?

A: Substitution is valid when the following parameters match: maximum voltage (16V), hold current rating (1.35A), trip current (2.7A), maximum current (40A), time to trip (4.5s), initial resistance (40 mOhms minimum), post-trip resistance (112 mOhms maximum), operating temperature range (-40°C to 85°C), mounting type (through hole), package configuration (radial disc), physical dimensions (0.350" L x 0.118" W), and lead spacing (0.199").

Q: Are there any compliance or certification differences between these parts?

A: No. Both RUSBF135-2 and RUSBF135-AP carry identical approvals from CSA, TUV, and UL agencies, and both meet ROHS3 compliance requirements.

Q: What is the difference between these two part numbers if all parameters are identical?

A: The part numbers reflect different packaging or distribution configurations within the Littelfuse PolySwitch® RUSBF series. The "-2" and "-AP" suffixes indicate variant designations, but the electrical and mechanical specifications are equivalent.

Q: Can these parts be used interchangeably in PCB designs?

A: Yes. Identical through-hole radial disc package configuration, lead spacing, and physical dimensions ensure PCB footprint compatibility. No design modifications are required for substitution.