T491B155M025AT Equivalent & Substitute Parts

Part Overview

The T491B155M025AT is a 1.5 µF molded tantalum capacitor manufactured by KEMET, rated for 25 V operation with ±20% capacitance tolerance. This surface mount component is housed in a 1411 (3528 Metric) package and features 5Ohm equivalent series resistance (ESR). The part is Active in product status and widely used in general-purpose applications requiring stable capacitance performance across the -55°C to 125°C operating temperature range. Equivalent and substitute parts are identified to support procurement flexibility, inventory management, and supply chain continuity for applications where the primary part number may have limited availability.

Substiute Parts

T491B155M025AT

KEMETIn Stock: 17319T491B155M025AT Datasheet

Current PartRFQ

T491B155K025AT

KEMETIn Stock: 49549T491B155K025AT Datasheet

SimilarRFQ

TAJB155M025RNJ

KYOCERA AVXIn Stock: 3504TAJB155M025RNJ Datasheet

DirectRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitute parts for the T491B155M025AT are identified based on strict electrical and mechanical parameter alignment. The substitution logic is organized into two categories:

Category 1: Same Manufacturer (KEMET) - Tolerance Variant The T491B155K025AT maintains identical electrical specifications (1.5 µF, 25 V, 5Ohm ESR) and mechanical compatibility (1411 package, surface mount) but features ±10% tolerance instead of ±20%. This tighter tolerance represents an upgrade path within the same product series (T491) and is directly substitutable where tolerance requirements permit.

Category 2: Cross-Manufacturer Equivalent (KYOCERA AVX) The TAJB155M025RNJ from KYOCERA AVX provides electrical equivalence (1.5 µF, 25 V, ±20% tolerance, 5Ohm ESR) and mechanical compatibility (1411/3528 Metric package, surface mount). This part enables supply chain diversification while maintaining identical functional performance.

Key Parameters Governing Substitution:

• Capacitance: 1.5 µF (exact match required)
• Voltage Rating: 25 V (exact match required)
• ESR: 5Ohm (exact match required)
• Package: 1411 (3528 Metric) (exact match required)
• Mounting Type: Surface Mount (exact match required)
• Operating Temperature: -55°C to 125°C (exact match required)

Parameter Comparison

Engineering Selection Recommendations

All three parts listed—T491B155M025AT, T491B155K025AT, and TAJB155M025RNJ—are Active products with full compliance to ROHS3, REACH Unaffected status, and MSL 1 (Unlimited) moisture sensitivity classification. Selection between these parts should be based on the following criteria:

T491B155M025AT (Primary Part): Select this KEMET part when ±20% capacitance tolerance meets circuit requirements and KEMET supply chain preference is established. Current inventory of 17,300 pieces supports immediate procurement.

T491B155K025AT (KEMET Tolerance Upgrade): Select this variant when circuit design requires tighter ±10% capacitance tolerance while maintaining KEMET manufacturer continuity. Higher inventory availability (49,486 pieces) supports large-volume procurement. Electrical and mechanical specifications are identical to the primary part except for improved tolerance.

TAJB155M025RNJ (Cross-Manufacturer Equivalent): Select this KYOCERA AVX part to diversify supply chain risk or when KEMET parts face allocation constraints. Electrical performance (1.5 µF, 25 V, 5Ohm ESR, ±20% tolerance) and mechanical compatibility (1411 package, surface mount) are equivalent to the primary part. Lower inventory (3,400 pieces) indicates secondary availability status.

All three parts support the full -55°C to 125°C operating temperature range and are suitable for general-purpose applications. Compliance certifications are uniform across all options.

Frequently Asked Questions (FAQ)

Q: Can T491B155K025AT replace T491B155M025AT in my circuit? A: Yes. The T491B155K025AT is directly substitutable. Both parts share identical capacitance (1.5 µF), voltage rating (25 V), ESR (5Ohm), package (1411), and operating temperature range (-55°C to 125°C). The only difference is capacitance tolerance: T491B155K025AT offers ±10% versus ±20% for the primary part. This represents an improvement in tolerance performance.

Q: Is TAJB155M025RNJ from KYOCERA AVX electrically equivalent to T491B155M025AT? A: Yes. The TAJB155M025RNJ provides electrical equivalence with identical capacitance (1.5 µF), voltage rating (25 V), tolerance (±20%), and ESR (5Ohm). Mechanical compatibility is confirmed through matching package designation (1411/3528 Metric), surface mount mounting type, and identical physical dimensions (0.138" L x 0.110" W, 2.10mm max height). Both parts operate across -55°C to 125°C.

Q: Will these substitute parts fit the same PCB footprint? A: Yes. All three parts use the 1411 (3528 Metric) package with identical dimensions: 0.138" L x 0.110" W (3.50mm x 2.80mm) and maximum seated height of 0.083" (2.10mm). PCB footprint compatibility is confirmed for direct substitution without layout modifications.

Q: What is the difference between ±20% and ±10% tolerance? A: Tolerance specifies the acceptable range of actual capacitance deviation from the nominal 1.5 µF value. ±20% tolerance (T491B155M025AT) allows capacitance between 1.2 µF and 1.8 µF. ±10% tolerance (T491B155K025AT) restricts the range to 1.35 µF to 1.65 µF. Tighter tolerance provides more predictable circuit performance but may have different pricing and availability.

Q: Are all three parts RoHS compliant? A: Yes. T491B155M025AT, T491B155K025AT, and TAJB155M025RNJ are all ROHS3 Compliant with REACH Unaffected status. All parts carry MSL 1 (Unlimited) moisture sensitivity classification, indicating no special moisture handling requirements during storage or assembly.

Q: Which part should I select for new designs? A: For new designs, evaluate based on tolerance requirements and supply chain strategy. If ±20% tolerance is acceptable, T491B155M025AT (KEMET) or TAJB155M025RNJ (KYOCERA AVX) are suitable. If tighter tolerance improves circuit performance, T491B155K025AT (KEMET, ±10%) is recommended. All three parts are Active products with established supply chains.

Q: What is ESR and why does it matter? A: ESR (Equivalent Series Resistance) is 5Ohm for all three parts. ESR affects the capacitor's ability to handle ripple current and influences circuit impedance at high frequencies. Matching ESR across substitute parts ensures equivalent performance in filtering, decoupling, and energy storage applications.