Equivalent & Substitute Parts for T491B155K025AS

Part Overview

The T491B155K025AS is a 1.5 µF molded tantalum capacitor rated at 25 V with ±10% tolerance, manufactured by KEMET in the 1411 (3528 Metric) package. This component is classified as obsolete, indicating discontinuation from the manufacturer. Identification of equivalent and substitute parts is necessary to maintain design continuity, ensure supply chain availability, and support ongoing production or repair requirements for applications utilizing this capacitor specification.

Substiute Parts

T491B155K025AS

KEMETIn Stock: 10211T491B155K025AS Datasheet

Current PartRFQ

T491B155K025AT

KEMETIn Stock: 49549T491B155K025AT Datasheet

DirectRFQ

TAJB155K025H

KYOCERA AVXIn Stock: 790TAJB155K025H Datasheet

DirectRFQ

293D155X9025B2TE3

Vishay SpragueIn Stock: 1837293D155X9025B2TE3 Datasheet

SimilarRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the T491B155K025AS is determined by strict equivalence across the following critical parameters:

Mandatory Matching Parameters:

• Capacitance: 1.5 µF
• Tolerance: ±10%
• Voltage Rating: 25 V
• Package / Case: 1411 (3528 Metric)
• Mounting Type: Surface Mount
• Operating Temperature Range: -55°C ~ 125°C
• Moisture Sensitivity Level: 1 (Unlimited)

Allowable Variation:

• ESR (Equivalent Series Resistance): Substitutes may vary within the range of 4.6 Ohm to 5 Ohm, provided the value does not exceed the original specification
• Product Status: Active status substitutes are preferred over obsolete status due to ongoing availability

The substitute parts identified below meet all mandatory matching parameters and fall within allowable ESR variation.

Parameter Comparison

Engineering Selection Recommendations

Primary Substitute: T491B155K025AT

The T491B155K025AT is the direct equivalent from KEMET, the original manufacturer of the T491B155K025AS. This part maintains identical electrical and mechanical specifications while offering active product status and ROHS3 compliance. The packaging format is Tape & Reel (TR), suitable for automated assembly processes. This substitute provides the highest level of design continuity and supply chain reliability.

Secondary Substitute: 293D155X9025B2TE3

The 293D155X9025B2TE3 from Vishay Sprague meets all mandatory electrical and mechanical parameters with an ESR of 4.6 Ohm, which is lower than the original 5 Ohm specification. This represents an improvement in performance characteristics. The part carries ROHS3 compliance and active product status. Tape & Reel packaging is available. The slightly lower ESR may provide marginal benefits in high-frequency applications.

Tertiary Substitute: TAJB155K025H

The TAJB155K025H from KYOCERA AVX meets all mandatory electrical and mechanical parameters. However, this part carries RoHS non-compliant status, matching the original part's compliance profile. Product status is active, ensuring availability. This substitute is suitable for applications where RoHS compliance is not a design requirement.

Compliance Considerations:

For applications requiring RoHS3 compliance, T491B155K025AT or 293D155X9025B2TE3 are the appropriate selections. For applications with no RoHS compliance requirement, all three substitutes are viable options based on availability and supply chain preferences.

Frequently Asked Questions (FAQ)

Q: Can T491B155K025AT be used as a direct replacement for T491B155K025AS?

A: Yes. T491B155K025AT is electrically and mechanically equivalent to T491B155K025AS. Both parts share identical capacitance (1.5 µF), tolerance (±10%), voltage rating (25 V), ESR (5 Ohm), operating temperature range (-55°C ~ 125°C), and package dimensions (1411 / 3528 Metric). The primary difference is product status: T491B155K025AT is active, while T491B155K025AS is obsolete.

Q: What is the difference between the packaging formats listed for these parts?

A: T491B155K025AS and TAJB155K025H do not specify packaging format in the provided data. T491B155K025AT is supplied in Tape & Reel (TR) format, which is standard for automated surface mount assembly. 293D155X9025B2TE3 is also supplied in Tape & Reel (TR) format. Tape & Reel packaging is compatible with pick-and-place equipment used in high-volume manufacturing.

Q: Is the ESR difference between 5 Ohm and 4.6 Ohm significant?

A: The ESR difference between the original part (5 Ohm) and 293D155X9025B2TE3 (4.6 Ohm) is 0.4 Ohm. This represents an 8% reduction in equivalent series resistance. In most general-purpose applications, this difference is not functionally significant. In high-frequency or high-current ripple applications, the lower ESR of 293D155X9025B2TE3 may provide marginal performance benefits.

Q: Are all substitute parts compatible with the same PCB footprint?

A: Yes. All substitute parts share the same package designation (1411 / 3528 Metric) and identical physical dimensions: 0.138" L x 0.110" W (3.50mm x 2.80mm) with maximum seated height of 0.083" (2.10mm). The 293D155X9025B2TE3 has a maximum seated height of 0.083" (2.11mm), which is within standard PCB assembly tolerances. All parts are compatible with the same PCB footprint.

Q: Which substitute should be selected for new designs?

A: For new designs, T491B155K025AT or 293D155X9025B2TE3 are recommended based on product status (both active) and compliance requirements. T491B155K025AT is preferred if design continuity with the original KEMET series is a priority. 293D155X9025B2TE3 is preferred if lower ESR performance is beneficial. Both parts carry ROHS3 compliance, suitable for modern manufacturing standards.

Q: What is the moisture sensitivity level, and does it affect handling?

A: All parts, including the original T491B155K025AS and all substitutes, carry MSL 1 (Unlimited) rating. This indicates the component has unlimited shelf life and requires no special moisture control during storage or handling. Standard ESD precautions for surface mount components remain applicable.