T491X687K004AT Equivalent & Substitute Parts

Part Overview

The T491X687K004AT is a 680 µF molded tantalum capacitor manufactured by KEMET, rated for 4 V operation in a 2917 (7343 Metric) surface mount package. This component is classified as Active product status and is designed for general purpose applications requiring stable capacitance and reliable performance across industrial temperature ranges. Substitute parts are identified when equivalent electrical specifications and mechanical compatibility are maintained within the allowed parameter tolerances for this capacitor category.

Substiute Parts

T491X687K004AT

KEMETIn Stock: 885T491X687K004AT Datasheet

Current PartRFQ

T494D687K004AT

KEMETIn Stock: 1321T494D687K004AT Datasheet

DirectRFQ

TPME687K004R0023

KYOCERA AVXIn Stock: 2254TPME687K004R0023 Datasheet

SimilarRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitute parts for the T491X687K004AT are qualified based on the following criteria:

Mandatory Matching Parameters:

• Capacitance: 680 µF
• Tolerance: ±10%
• Voltage Rating: 4 V
• Package / Case: 2917 (7343 Metric)
• Mounting Type: Surface Mount
• Operating Temperature Range: -55°C ~ 125°C
• Type: Molded Tantalum

Variable Parameters (Allowed to Differ):

• ESR (Equivalent Series Resistance)
• Height - Seated (Max)
• Manufacturer Size Code
• Lifetime @ Temp. specifications
• Moisture Sensitivity Level

Parts meeting all mandatory matching parameters are classified as direct substitutes. The T494D687K004AT from KEMET and TPME687K004R0023 from KYOCERA AVX both satisfy these criteria.

Parameter Comparison

Engineering Selection Recommendations

T494D687K004AT (KEMET): This direct substitute maintains identical electrical and mechanical specifications with the exception of reduced ESR (150mOhm @ 100kHz versus 500mOhm) and lower seated height (3.10mm versus 4.30mm). Both parts are ROHS3 compliant with MSL 1 rating. The T494D series offers improved performance characteristics while maintaining full compatibility with the T491X footprint and electrical requirements.

TPME687K004R0023 (KYOCERA AVX): This substitute provides the same capacitance, voltage rating, tolerance, and package dimensions as the main part. The TPME series features significantly lower ESR (23mOhm) compared to the T491X (500mOhm). The MSL rating differs at Level 3 (168 Hours) versus Level 1 (Unlimited), requiring consideration of moisture exposure during storage and assembly. All parts maintain ROHS3 compliance and REACH Unaffected status.

Selection between substitutes depends on ESR requirements, moisture sensitivity constraints, and seated height clearance in the target application. All three parts are Active status components suitable for direct PCB assembly replacement.

Frequently Asked Questions (FAQ)

Q: Can T494D687K004AT replace T491X687K004AT in any application?

A: Yes, the T494D687K004AT is a direct substitute meeting all mandatory electrical and mechanical parameters. The reduced seated height (3.10mm versus 4.30mm) and lower ESR (150mOhm versus 500mOhm) are compatible with T491X footprints and may provide improved performance in applications sensitive to series resistance.

Q: What is the significance of the ESR difference between these parts?

A: ESR (Equivalent Series Resistance) affects ripple current handling, thermal performance, and frequency response. The T491X (500mOhm) has higher ESR than T494D (150mOhm) and TPME (23mOhm). Lower ESR reduces heat generation and improves high-frequency performance. Selection depends on application ripple current and thermal requirements.

Q: Why does TPME687K004R0023 have MSL 3 instead of MSL 1?

A: Moisture Sensitivity Level (MSL) indicates the maximum time a component can be exposed to moisture before soldering. MSL 1 (Unlimited) allows indefinite storage, while MSL 3 (168 Hours) requires controlled storage conditions. TPME components require desiccant packaging and limited exposure time before assembly.

Q: Are all three parts suitable for -55°C to 125°C operating range?

A: Yes, all three parts are rated for -55°C ~ 125°C operating temperature range. The T491X and T494D specify 2000 Hrs @ 125°C lifetime. TPME lifetime specifications are not provided in the available data.

Q: Can these parts be used interchangeably on existing PCBs?

A: Yes, all three parts use identical 2917 (7343 Metric) packages with matching footprints (0.287" L x 0.169" W). The T494D seated height is lower (3.10mm versus 4.30mm), which may affect clearance in space-constrained designs but does not prevent PCB-level substitution.

Q: What compliance certifications apply to all substitute parts?

A: All three parts are ROHS3 compliant and REACH Unaffected. Packaging is Tape & Reel (TR) format. ECCN classification is EAR99 for all parts. HTSUS code 8532.21.0050 applies to all molded tantalum capacitors in this category.