T491B155K025AH Equivalent & Substitute Parts

Part Overview

The T491B155K025AH is a 1.5 µF molded tantalum capacitor manufactured by KEMET, rated for 25 V operation with ±10% tolerance. This surface mount component is housed in a 1411 (3528 Metric) package and is designed for general purpose applications requiring stable capacitance in the -55°C to 125°C operating range. The part is currently in active production status with 852 pieces available in inventory.

Equivalent and substitute parts are identified when component availability is limited, supply chain disruptions occur, or design requirements necessitate alternative electrical characteristics such as reduced equivalent series resistance (ESR) or improved regulatory compliance.

Substiute Parts

T491B155K025AH

KEMETIn Stock: 890T491B155K025AH Datasheet

Current PartRFQ

T494B155K025AT

KEMETIn Stock: 3224T494B155K025AT Datasheet

Parametric EquivalentRFQ

TCKIE155BT

Cal-Chip Electronics, Inc.In Stock: 17099TCKIE155BT Datasheet

Parametric EquivalentRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the T491B155K025AH is determined by strict alignment of the following critical parameters:

Mandatory Matching Parameters:

• Capacitance: 1.5 µF
• Tolerance: ±10%
• Voltage Rating: 25 V
• Package / Case: 1411 (3528 Metric)
• Physical Dimensions: 0.138" L x 0.110" W (3.50mm x 2.80mm)
• Height - Seated (Max): 0.083" (2.10mm)
• Mounting Type: Surface Mount
• Operating Temperature Range: -55°C to 125°C
• Lifetime @ Temp.: 2000 Hrs @ 125°C
• Moisture Sensitivity Level: 1 (Unlimited)

Variable Parameters (Non-Critical for Substitution):

• Equivalent Series Resistance (ESR): May vary within acceptable circuit performance limits
• Manufacturer: Different manufacturers permitted
• RoHS Status: May differ between main part and substitute
• Series Designation: Different series acceptable

The identified substitute parts T494B155K025AT and TCKIE155BT satisfy all mandatory matching parameters and are therefore classified as parametric equivalents.

Parameter Comparison

Engineering Selection Recommendations

T494B155K025AT (KEMET): This substitute offers identical electrical and mechanical specifications to the T491B155K025AH with the following distinctions: reduced ESR of 1.5 Ohm at 100kHz compared to 5 Ohm in the main part, and ROHS3 compliance status. The T494B155K025AT is suitable for applications where lower ESR performance is beneficial and regulatory compliance with ROHS3 standards is required. Inventory availability is significantly higher at 3198 pieces.

TCKIE155BT (Cal-Chip Electronics, Inc.): This substitute maintains identical electrical and mechanical specifications to the T491B155K025AH, including matching ESR of 5 Ohm. The TCKIE155BT is RoHS compliant and offers the highest inventory availability at 17053 pieces. This part is appropriate for applications requiring RoHS compliance and maximum supply chain availability.

Selection between substitutes should be based on regulatory compliance requirements (RoHS status), ESR performance needs, and inventory availability for the specific application.

Frequently Asked Questions (FAQ)

Q: Can T494B155K025AT be used as a direct replacement for T491B155K025AH?

A: Yes. Both parts share identical capacitance (1.5 µF), tolerance (±10%), voltage rating (25 V), package (1411 / 3528 Metric), physical dimensions, operating temperature range (-55°C to 125°C), and lifetime specifications (2000 Hrs @ 125°C). The T494B155K025AT features lower ESR (1.5 Ohm @ 100kHz versus 5 Ohm) and ROHS3 compliance, making it suitable for direct substitution in applications where these characteristics are acceptable or beneficial.

Q: Can TCKIE155BT be used as a direct replacement for T491B155K025AH?

A: Yes. The TCKIE155BT matches all critical electrical and mechanical parameters of the T491B155K025AH, including capacitance, tolerance, voltage rating, package dimensions, operating temperature range, and lifetime specifications. ESR is identical at 5 Ohm. The primary difference is manufacturer (Cal-Chip Electronics, Inc. versus KEMET) and RoHS compliance status.

Q: What is the significance of ESR differences between the main part and T494B155K025AT?

A: ESR (Equivalent Series Resistance) affects circuit performance in high-frequency applications and power dissipation characteristics. The T494B155K025AT has lower ESR (1.5 Ohm @ 100kHz) compared to the T491B155K025AH (5 Ohm). Lower ESR reduces heat generation and improves performance in noise-sensitive or high-frequency filtering applications. Circuit design validation is necessary to confirm compatibility with the specific application.

Q: Are all three parts available in the same packaging format?

A: Yes. The T491B155K025AH, T494B155K025AT, and TCKIE155BT are all supplied in Tape & Reel (TR) packaging, suitable for automated assembly processes.

Q: What is Moisture Sensitivity Level (MSL) 1, and why is it important?

A: MSL 1 indicates unlimited shelf life without moisture exposure restrictions. All three parts carry MSL 1 rating, meaning they do not require special moisture-controlled storage conditions and can be stored under standard industrial conditions without degradation.

Q: How do RoHS compliance differences affect part selection?

A: The T491B155K025AH is RoHS non-compliant, while T494B155K025AT is ROHS3 compliant and TCKIE155BT is RoHS compliant. Selection depends on regulatory requirements for the end application. Applications subject to RoHS directives require compliant components. Non-regulated applications may use any of the three parts.

Q: What inventory considerations should influence part selection?

A: Current inventory levels are T491B155K025AH (852 pcs), T494B155K025AT (3198 pcs), and TCKIE155BT (17053 pcs). Higher inventory availability reduces lead time risk and supply chain uncertainty. TCKIE155BT offers the most robust supply position.