T491D476M025AS Equivalent & Substitute Parts

Part Overview

The T491D476M025AS is a 47 µF molded tantalum capacitor manufactured by KEMET, rated for 25 V operation in a 2917 (7343 Metric) surface mount package. This component is classified as obsolete, indicating discontinuation from active production. The part features a ±20% capacitance tolerance, 700 mOhm equivalent series resistance (ESR), and operates across the temperature range of -55°C to 125°C. Due to its obsolete status, direct replacement with active production equivalents or functionally superior alternatives is necessary for new designs and ongoing procurement requirements.

Key Parameters

Parameter	Value	Unit
Capacitance	47	µF
Voltage Rating	25	V
Tolerance	±20%	—
ESR (Equivalent Series Resistance)	700	mOhm
Package / Case	2917 (7343 Metric)	—
Mounting Type	Surface Mount	—
Operating Temperature Range	-55 to 125	°C
Type	Molded Tantalum	—
RoHS Status	ROHS3 Compliant	—
MSL (Moisture Sensitivity Level)	1 (Unlimited)	—

Substitute Part Grouping Explanation

Substitution of the T491D476M025AS is determined by strict adherence to the following electrical and mechanical parameters:

Primary Substitution Criteria:

Capacitance: 47 µF (exact match required)
Voltage Rating: 25 V (exact match required)
Package / Case: 2917 (7343 Metric) (exact match required)
Mounting Type: Surface Mount (exact match required)
Operating Temperature Range: -55°C to 125°C (exact match required)

Secondary Substitution Parameters (Allow Variation):

Tolerance: ±20% or tighter (±10% acceptable as upgrade)
ESR: 700 mOhm or lower (lower ESR represents performance improvement)
Product Status: Active preferred over obsolete
Lifetime @ Temperature: 2000 Hrs @ 125°C or 2000 Hrs @ 85°C (active parts)

Substitute parts are grouped into three categories:

Direct Substitutes (Same Electrical & Mechanical Specifications): Parts with identical capacitance, voltage, tolerance, ESR, package, and temperature range. These provide one-to-one replacement capability.

Upgrade Substitutes (Improved Tolerance or ESR): Parts maintaining all primary parameters but offering tighter tolerance (±10% vs. ±20%) or lower ESR (120–200 mOhm vs. 700 mOhm), providing enhanced performance characteristics.

Similar Substitutes (Different Manufacturer, Equivalent Specifications): Parts from alternative manufacturers (KYOCERA AVX, Vishay Sprague) meeting all primary electrical and mechanical requirements, enabling multi-source procurement strategies.

Parameter Comparison

Part Number	Manufacturer	Capacitance (µF)	Voltage (V)	Tolerance	ESR (mOhm)	Package	Product Status	Lifetime @ Temp.
T491D476M025AS	KEMET	47	25	±20%	700	2917	Obsolete	—
T491D476M025AT	KEMET	47	25	±20%	700	2917	Active	2000 Hrs @ 125°C
T491D476K025AT	KEMET	47	25	±10%	700	2917	Active	2000 Hrs @ 125°C
T494D476M025AG	KEMET	47	25	±20%	200	2917	Active	2000 Hrs @ 125°C
T494D476M025AT	KEMET	47	25	±20%	200	2917	Active	2000 Hrs @ 125°C
T495D476M025ATE120	KEMET	47	25	±20%	120	2917	Active	2000 Hrs @ 85°C
T495X476M025ATE200	KEMET	47	25	±20%	200	2917	Active	2000 Hrs @ 85°C
F931E476KNC	KYOCERA AVX	47	25	±10%	700 @ 100kHz	2917	Active	2000 Hrs @ 125°C
F931E476MNC	KYOCERA AVX	47	25	±20%	700 @ 100kHz	2917	Active	2000 Hrs @ 125°C
293D476X9025D2TE3	Vishay Sprague	47	25	±10%	700	2917	Active	—
293D476X0025D2TE3	Vishay Sprague	47	25	±20%	700 @ 100kHz	2917	Active	—

Engineering Selection Recommendations

For Direct Replacement (Identical Specifications):

T491D476M025AT (KEMET) is the primary direct substitute. This part maintains all electrical and mechanical parameters of the T491D476M025AS while offering active product status and documented lifetime rating of 2000 hours at 125°C. The transition from obsolete to active status ensures long-term availability and supply chain stability.

F931E476MNC (KYOCERA AVX) provides an alternative direct substitute from a different manufacturer, maintaining ±20% tolerance and 700 mOhm ESR specifications. This part is ROHS3 compliant and carries active product status, supporting multi-source procurement strategies.

293D476X0025D2TE3 (Vishay Sprague) offers equivalent electrical performance with active status. ESR specification is measured at 100 kHz, consistent with industry measurement standards for tantalum capacitors.

For Performance Enhancement (Tighter Tolerance):

T491D476K025AT (KEMET) upgrades tolerance from ±20% to ±10% while maintaining all other parameters. This part is recommended for applications requiring improved capacitance accuracy without ESR modification.

F931E476KNC (KYOCERA AVX) provides ±10% tolerance with 700 mOhm ESR from an alternative manufacturer, supporting design flexibility and supply diversification.

293D476X9025D2TE3 (Vishay Sprague) delivers ±10% tolerance with active product status and ROHS3 compliance.

For ESR Reduction (Lower Impedance):

T494D476M025AT (KEMET) reduces ESR from 700 mOhm to 200 mOhm, improving high-frequency performance and reducing voltage ripple. Recommended for applications with stringent ripple current or transient response requirements.

T495D476M025ATE120 (KEMET) provides the lowest ESR at 120 mOhm, optimizing performance in noise-sensitive circuits. Lifetime rating is specified at 2000 hours at 85°C.

T495X476M025ATE200 (KEMET) offers 200 mOhm ESR with active status and documented reliability data.

Compliance & Certification:

All substitute parts listed are ROHS3 compliant and carry MSL rating of 1 (Unlimited), matching the original part's environmental and handling specifications. REACH status is unaffected for all alternatives, ensuring regulatory compatibility across global markets.

Frequently Asked Questions (FAQ)

Q: Can T491D476M025AT be used as a direct replacement for T491D476M025AS?

A: Yes. T491D476M025AT is a direct substitute with identical electrical specifications (47 µF, 25 V, ±20%, 700 mOhm ESR) and mechanical package (2917). The primary difference is product status: T491D476M025AT is active with documented 2000-hour lifetime at 125°C, while T491D476M025AS is obsolete. This substitution is recommended for all new designs and ongoing procurement.

Q: What is the difference between KEMET T491, T494, and T495 series?

A: These series differ in ESR specification. T491 series specifies 700 mOhm ESR. T494 series reduces ESR to 200 mOhm. T495 series provides the lowest ESR at 120–200 mOhm depending on part number suffix. All three series maintain identical capacitance (47 µF), voltage (25 V), package (2917), and temperature range (-55°C to 125°C). Selection depends on application requirements for ripple current handling and transient response.

Q: Are KYOCERA AVX F931E476MNC and KEMET T491D476M025AT interchangeable?

A: Yes, with one measurement specification difference. Both parts specify 47 µF, 25 V, ±20% tolerance, and 700 mOhm ESR in the 2917 package. KYOCERA AVX specifies ESR at 100 kHz measurement frequency, while KEMET does not specify frequency. Both parts are ROHS3 compliant with MSL 1 rating. Physical dimensions are identical (0.287" L × 0.169" W × 0.122" H maximum). Interchangeability is confirmed for all electrical and mechanical parameters.

Q: What does ±10% tolerance upgrade mean for circuit performance?

A: Tolerance specification defines the allowable deviation from nominal capacitance value. ±20% tolerance permits capacitance values between 37.6 µF and 56.4 µF. ±10% tolerance restricts the range to 42.3 µF to 51.7 µF. Tighter tolerance reduces circuit parameter variation, improving predictability in applications sensitive to capacitance accuracy such as timing circuits, filtering networks, and frequency-dependent designs. Parts T491D476K025AT, F931E476KNC, and 293D476X9025D2TE3 offer this upgrade.

Q: How does ESR reduction from 700 mOhm to 120 mOhm affect circuit operation?

A: Lower ESR reduces impedance at high frequencies, decreasing voltage ripple across the capacitor and improving transient response. Applications with high ripple current requirements, fast switching transients, or noise-sensitive analog circuits benefit from ESR reduction. T495D476M025ATE120 (120 mOhm) provides maximum performance improvement. T494 series (200 mOhm) offers moderate improvement with broader availability. Selection depends on specific circuit requirements and thermal management considerations.

Q: Are packaging differences between Cut Tape (CT) and Tape & Reel (TR) significant for substitution?

A: Packaging format affects procurement and assembly logistics but does not impact electrical or mechanical compatibility. Cut Tape (CT) & Digi-Reel® packaging suits lower-volume applications and manual assembly. Tape & Reel (TR) packaging optimizes high-volume automated assembly. Both formats contain identical components in the same 2917 package. Substitution is valid regardless of packaging format; selection depends on production volume and assembly equipment compatibility.

Q: What is MSL 1 (Unlimited) moisture sensitivity rating?

A: MSL (Moisture Sensitivity Level) 1 indicates the component requires no special moisture control during storage, handling, or assembly. Components rated MSL 1 can be stored at room temperature without desiccant protection and do not require baking before soldering. All substitute parts listed carry MSL 1 rating, matching the original T491D476M025AS specification and eliminating moisture management requirements.

Q: Can Vishay Sprague 293D476X0025D2TE3 replace KEMET T491D476M025AS in existing designs?

A: Yes. Both parts specify 47 µF, 25 V, ±20% tolerance, 700 mOhm ESR, and 2917 package with identical physical dimensions. Vishay Sprague part is active with ROHS3 compliance and MSL 1 rating. ESR is specified at 100 kHz measurement frequency. This substitution supports multi-source procurement and supply chain resilience. Electrical and mechanical compatibility is confirmed for all parameters.

Q: What lifetime rating should be considered for reliability-critical applications?

A: Lifetime rating specifies capacitor reliability under specified temperature conditions. KEMET T491D476M025AT specifies 2000 hours at 125°C. KEMET T495D476M025ATE120 specifies 2000 hours at 85°C. Higher temperature ratings (125°C) indicate more stringent reliability testing. For applications operating near maximum temperature limits, parts with 125°C lifetime ratings are preferred. Vishay Sprague 293D series does not specify lifetime in provided data; contact manufacturer for reliability specifications if required for critical applications.

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