T494X156K035AT Equivalent & Substitute Parts

Part Overview

The T494X156K035AT is an active, ROHS3-compliant molded tantalum capacitor manufactured by KEMET. This 15 µF, 35 V surface mount component is designed for general purpose applications requiring stable capacitance performance across the -55°C to 125°C operating temperature range. The part is specified with 300mOhm ESR at 100kHz and rated for 2000 hours lifetime at 125°C. Identifying equivalent and substitute parts is necessary when the primary part number becomes unavailable, when inventory constraints require alternative sourcing, or when design flexibility permits selection from qualified alternatives within the same electrical and mechanical specifications.

Substiute Parts

T494X156K035AT

KEMETIn Stock: 895T494X156K035AT Datasheet

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T491X156K035AT

KEMETIn Stock: 2778T491X156K035AT Datasheet

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Key Parameters

Substitute Part Grouping Explanation

Substitution of the T494X156K035AT is permitted only when the replacement part maintains identical electrical and mechanical specifications across all critical parameters. The substitution logic is based strictly on the following criteria:

Critical Parameters (Must Match Exactly):

• Capacitance: 15 µF
• Voltage Rating: 35 V
• Tolerance: ±10%
• Package / Case: 2917 (7343 Metric)
• Mounting Type: Surface Mount
• Operating Temperature Range: -55°C to 125°C
• Component Type: Molded Tantalum

Application-Dependent Parameters (Variation Permitted Within Limits):

• ESR @ 100kHz: The main part specifies 300mOhm. Substitute parts with higher ESR values may be acceptable depending on circuit ripple current requirements and thermal dissipation constraints.
• Lifetime @ 125°C: Both the main part and substitute are rated for 2000 hours at 125°C, establishing a baseline reliability specification.

Compliance Parameters (Must Maintain):

• RoHS3 Compliance
• MSL Rating 1 (Unlimited)

The T491X156K035AT qualifies as a substitute based on matching all critical parameters while differing only in ESR specification (900mOhm versus 300mOhm).

Parameter Comparison

Engineering Selection Recommendations

T491X156K035AT as Substitute for T494X156K035AT:

The T491X156K035AT is a qualified substitute based on identical electrical ratings (15 µF, 35 V, ±10% tolerance), matching mechanical package specifications (2917 / 7343 Metric), and equivalent compliance certifications (ROHS3, MSL 1). Both parts are manufactured by KEMET and maintain active product status.

The primary difference between these parts is the ESR specification: T494X156K035AT specifies 300mOhm at 100kHz, while T491X156K035AT specifies 900mOhm. This difference affects ripple current handling and thermal dissipation characteristics. Selection between these parts depends on circuit requirements for maximum allowable ESR. Applications with strict ripple current or thermal constraints may require the lower ESR T494X156K035AT. Applications with less stringent ESR requirements can accommodate the T491X156K035AT.

Both parts satisfy identical operating temperature ranges (-55°C to 125°C) and lifetime specifications (2000 hours at 125°C), ensuring equivalent reliability performance in qualified applications.

Frequently Asked Questions (FAQ)

Q: Can T491X156K035AT replace T494X156K035AT in any application?

A: The T491X156K035AT is electrically and mechanically compatible with T494X156K035AT for applications where the higher ESR value (900mOhm versus 300mOhm) does not exceed circuit ripple current or thermal dissipation limits. Circuit analysis is required to confirm ESR compatibility.

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

A: ESR (Equivalent Series Resistance) determines the capacitor's ability to handle ripple current and dissipate heat. The T494X156K035AT with 300mOhm ESR handles higher ripple currents with lower heat generation. The T491X156K035AT with 900mOhm ESR generates more heat under identical ripple current conditions. Selection depends on circuit ripple current specifications.

Q: Are both parts physically identical?

A: Yes. Both parts use the 2917 (7343 Metric) package with identical dimensions (0.287" L x 0.169" W, 7.30mm x 4.30mm) and maximum seated height (0.169" / 4.30mm). Both are surface mount components suitable for identical PCB layouts.

Q: Do both parts meet the same compliance requirements?

A: Yes. Both T494X156K035AT and T491X156K035AT are ROHS3 compliant, carry MSL Rating 1 (Unlimited moisture sensitivity), and maintain active product status from KEMET.

Q: What is the difference between T494 and T491 series designations?

A: The series designation reflects the internal design and performance characteristics of the molded tantalum capacitor. T494 and T491 are distinct KEMET series with different ESR specifications. Both series meet the same electrical ratings (15 µF, 35 V) and package standards for this application.

Q: Can I use T491X156K035AT if T494X156K035AT is not available?

A: Substitution is permitted only after confirming that the circuit design accommodates the higher ESR value of the T491X156K035AT. If circuit ripple current or thermal analysis confirms compatibility with 900mOhm ESR, the T491X156K035AT is a valid substitute.

Q: Are there any temperature or reliability differences between these parts?

A: No. Both parts operate across the identical temperature range (-55°C to 125°C) and carry identical lifetime ratings (2000 hours at 125°C). Thermal performance differences result only from the ESR variation.