T491D686K020AS Equivalent & Substitute Parts

Part Overview

The T491D686K020AS is a 68 µF molded tantalum capacitor rated at 20 V with ±10% tolerance, manufactured by KEMET in the 2917 (7343 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 and ensure component availability for production, repair, and long-term system support.

Substiute Parts

T491D686K020AS

KEMETIn Stock: 2310T491D686K020AS Datasheet

Current PartRFQ

T491D686K020AT

KEMETIn Stock: 1174T491D686K020AT Datasheet

DirectRFQ

293D686X9020D2TE3

Vishay SpragueIn Stock: 2358293D686X9020D2TE3 Datasheet

SimilarRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the T491D686K020AS is determined by strict equivalence across the following critical parameters:

• Capacitance Value: 68 µF (exact match required)
• Voltage Rating: 20 V (exact match required)
• Tolerance: ±10% (exact match required)
• ESR: 700 mOhm (exact match required)
• Package / Case: 2917 (7343 Metric) (exact match required for PCB compatibility)
• Physical Dimensions: 0.287" L × 0.169" W, Height 0.122" max (exact match required for mechanical fit)
• Operating Temperature Range: -55°C to 125°C (exact match required)
• Mounting Type: Surface Mount (exact match required)

Substitute parts must satisfy all parameters listed above. The following parts meet these criteria and are classified as direct equivalents or active alternatives.

Parameter Comparison

Engineering Selection Recommendations

T491D686K020AT (KEMET - Recommended Primary Substitute)

The T491D686K020AT is the direct equivalent replacement for the obsolete T491D686K020AS. Both parts are manufactured by KEMET within the same T491 series and share identical electrical and mechanical specifications. The T491D686K020AT maintains active product status and is ROHS3 compliant, providing regulatory compliance for new designs and production environments. This part includes a specified lifetime rating of 2000 hours at 125°C, offering documented reliability data. Packaging is available in Cut Tape (CT) and Digi-Reel® formats, supporting both manual and automated assembly processes.

293D686X9020D2TE3 (Vishay Sprague - Alternative Substitute)

The 293D686X9020D2TE3 from Vishay Sprague is a cross-manufacturer equivalent that satisfies all critical electrical and mechanical parameters. This part is active in production and ROHS3 compliant. It is supplied in Tape & Reel (TR) packaging, suitable for high-volume automated assembly. Selection of this part introduces a secondary-source strategy, reducing supply chain dependency on a single manufacturer while maintaining full electrical and mechanical compatibility.

Both substitute parts are suitable for direct PCB replacement without design modification, provided that the original design does not include manufacturer-specific performance requirements beyond the specified parameters.

Frequently Asked Questions (FAQ)

Q: Can T491D686K020AT be used as a direct replacement for T491D686K020AS?

A: Yes. The T491D686K020AT is a direct equivalent. Both parts share identical capacitance (68 µF), voltage rating (20 V), tolerance (±10%), ESR (700 mOhm), package (2917/7343 Metric), physical dimensions, and operating temperature range (-55°C to 125°C). The primary difference is product status: T491D686K020AS is obsolete, while T491D686K020AT is active and ROHS3 compliant.

Q: Is the 293D686X9020D2TE3 compatible with designs using T491D686K020AS?

A: Yes. The 293D686X9020D2TE3 meets all electrical and mechanical specifications required for substitution. It provides identical capacitance, voltage, tolerance, ESR, package dimensions, and operating temperature range. The cross-manufacturer design allows for supply chain flexibility while maintaining full circuit compatibility.

Q: What are the packaging differences between substitute parts?

A: T491D686K020AT is available in Cut Tape (CT) and Digi-Reel® packaging. The 293D686X9020D2TE3 is supplied in Tape & Reel (TR) format. Both packaging types are standard for surface-mount tantalum capacitors and are compatible with automated pick-and-place assembly equipment. Selection depends on production volume and assembly line configuration.

Q: Are there compliance differences between the main part and substitutes?

A: Yes. The T491D686K020AS is RoHS non-compliant. Both substitute parts (T491D686K020AT and 293D686X9020D2TE3) are ROHS3 compliant. For applications requiring regulatory compliance with RoHS directives, the substitute parts are required.

Q: Will the substitutes fit the same PCB footprint?

A: Yes. All three parts use the 2917 (7343 Metric) package with identical physical dimensions: 0.287" L × 0.169" W (7.30 mm × 4.30 mm) and maximum seated height of 0.122" (3.10 mm). No PCB layout modification is required.

Q: What is the significance of the 700 mOhm ESR specification?

A: ESR (Equivalent Series Resistance) of 700 mOhm is a critical electrical parameter that affects circuit performance, particularly in filtering and decoupling applications. All substitute parts maintain this exact ESR value, ensuring equivalent electrical behavior in the circuit.

Q: Are there lifetime or reliability differences?

A: The T491D686K020AT specifies a lifetime of 2000 hours at 125°C. The T491D686K020AS and 293D686X9020D2TE3 do not include specified lifetime data in the provided parameters. For applications requiring documented reliability metrics, the T491D686K020AT is the preferred choice.