T491A686K004AS Equivalent & Substitute Parts

Part Overview

The T491A686K004AS is a 68 µF molded tantalum capacitor manufactured by KEMET, rated for 4 V operation in a 1206 (3216 Metric) surface mount package. This component is classified as obsolete, indicating discontinuation from active production. The substitute part T491A686K004AT provides functional equivalence with active product status and improved compliance certifications, making it the primary alternative for new designs and ongoing production requirements.

Substiute Parts

T491A686K004AS

KEMETIn Stock: 828T491A686K004AS Datasheet

Current PartRFQ

T491A686K004AT

KEMETIn Stock: 1133T491A686K004AT Datasheet

DirectRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the T491A686K004AS is determined by strict equivalence across all electrical and mechanical parameters. The substitute part T491A686K004AT maintains identical specifications for capacitance (68 µF), voltage rating (4 V), tolerance (±10%), ESR (4 Ohm), package type (1206/3216 Metric), operating temperature range (-55°C ~ 125°C), and mounting configuration (Surface Mount). Both components are molded tantalum capacitors with identical physical dimensions and electrical characteristics.

The primary distinction between these parts is product status and packaging format. The T491A686K004AS is supplied in cut tape format and carries obsolete status. The T491A686K004AT is supplied in Tape & Reel (TR) format and maintains active product status with ROHS3 compliance certification and documented lifetime rating of 2000 Hrs @ 125°C.

Parameter Comparison

Engineering Selection Recommendations

The T491A686K004AT is the direct functional equivalent for applications currently using or requiring the T491A686K004AS. Selection of the substitute part is based on the following engineering criteria:

Product Status: The T491A686K004AS is obsolete and no longer in active production. The T491A686K004AT maintains active product status with ongoing manufacturer support and availability.

Regulatory Compliance: The T491A686K004AT carries ROHS3 compliance certification, meeting current regulatory requirements for electronic components in regulated markets. The original part is RoHS non-compliant.

Reliability Documentation: The T491A686K004AT includes documented lifetime rating of 2000 Hrs @ 125°C, providing quantified reliability data for design validation and qualification processes.

Packaging Compatibility: Both parts are identical in electrical and mechanical specifications. The T491A686K004AT is supplied in standard Tape & Reel (TR) format, suitable for automated assembly processes. The original part was supplied in cut tape format.

PCB Integration: No PCB redesign is required. The identical 1206 (3216 Metric) package footprint, dimensions (0.126" L x 0.063" W / 3.20mm x 1.60mm), and maximum seated height (0.071" / 1.80mm) ensure direct mechanical and electrical compatibility.

For new designs, production continuity, or component replenishment, the T491A686K004AT is the appropriate selection.

Frequently Asked Questions (FAQ)

Q: Can T491A686K004AT be used as a direct replacement for T491A686K004AS in existing designs?

A: Yes. Both parts are electrically and mechanically identical across all specified parameters: 68 µF capacitance, 4 V rating, ±10% tolerance, 4 Ohm ESR, 1206 package, and -55°C ~ 125°C operating range. No circuit modifications or PCB redesign are required.

Q: What is the primary reason to switch from T491A686K004AS to T491A686K004AT?

A: The T491A686K004AS is obsolete and no longer manufactured. The T491A686K004AT is the active equivalent with identical electrical performance, improved regulatory compliance (ROHS3), and documented reliability specifications.

Q: Are there any differences in physical dimensions between these parts?

A: No. Both parts share identical dimensions: 0.126" L x 0.063" W (3.20mm x 1.60mm) with maximum seated height of 0.071" (1.80mm). They use the same 1206 (3216 Metric) surface mount package.

Q: What is the difference in packaging format?

A: The T491A686K004AS was supplied in cut tape format. The T491A686K004AT is supplied in Tape & Reel (TR) format, which is standard for automated assembly operations and provides better handling for high-volume production.

Q: Does the T491A686K004AT meet current regulatory requirements?

A: Yes. The T491A686K004AT is ROHS3 compliant and REACH unaffected, meeting current regulatory standards for electronic components. The original T491A686K004AS is RoHS non-compliant.

Q: Is there a documented reliability specification for the substitute part?

A: Yes. The T491A686K004AT has a documented lifetime rating of 2000 Hrs @ 125°C. The original part does not include a specified lifetime rating.

Q: Will the substitute part function identically in the same circuit?

A: Yes. Identical electrical specifications (capacitance, voltage, tolerance, ESR) and operating temperature range ensure identical circuit performance.

Q: Are both parts from the same manufacturer?

A: Yes. Both T491A686K004AS and T491A686K004AT are manufactured by KEMET and belong to the T491 series of molded tantalum capacitors.