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T491R227M035AH

Surface Mount Capacitors

KEMET 

SOLID TANTALUM CHIP CAPACITORS

TANTALUM MnO2 COMPONENT PERFORMANCE CHARACTERISTICS

Introduction

KEMET solid tantalum capacitors are identified by

the initial “T,” followed by a unique “Series” num-

ber; for example, T491, T492, etc. Each Series

denotes a general physical form and type of

encapsulation, as well as limits on dimensions and

certain electrical characteristics under standard

conditions of 25°C, 50% relative humidity, and one

atmosphere pressure. Specific requirements are

set forth in the respective Product Series in this

catalog. All series are 100% screened for leakage,

capacitance, dissipation factor, and ESR. All

Series are inspected to electrical limits using a

minimum .1% AQL sampling plan, according to

the Military Standard MIL-STD-105, even after

100% testing. This sampling plan, to the best of

KEMET Electronics’ knowledge, meets or exceeds

the generally accepted industry standard for simi-

lar products. KEMET capacitors may also be sup-

plied, with prior agreement, to meet specifications

with requirements differing from those of KEMET cat-

alogs.

ELECTRICAL

of equilibrium with the environment, is approxi-

mately -5% to +12% over the range from 25% to

95% RH, referred to the standard 50% RH. The

amount of change is dependent upon size (capaci-

tance and voltage rating, ie: CV product); small

sizes might change no more than ±5%.

Equilibrium at such extremes is seldom attained by

plastic-cased capacitors, and the change in

capacitance is consequently less. The rate of

response to humidity changes increases with

increasing temperature. Dissipation factor and

ESR also increase with increasing RH.

DC leakage current may rise upon exposure to a

combination of high temperature and high humidi-

ty, but is normally restored by voltage conditioning

under standard conditions. The increase will be

greater than that experienced under temperature

influence alone because of conduction through

absorbed water.

Tantalum chips may be affected by absorption of

water on external insulating surfaces.The water

film may also attract a layer of dust from the air,

increasing the effect. The most sensitive parame-

ter is leakage current.

1. General Application Class

Solid tantalum capacitors are usually applied in

circuits where the AC component is small com-

pared to the DC component. Typical uses known

to KEMET Electronics include blocking, by-pass-

ing, decoupling, and filtering. They are also used in

timing circuits. General purpose devices are rec-

ommended to have an external series resistance of

0.1Ω/volt to reduce the failure due to surge cur-

rent. Newer devices designed for power applica-

tions (T495, T5XX), are built to eliminate this series

resistance requirement. Because tantalum capaci-

tors can experience scintillation (self-healing) in

their life, the circuit impedence should not exceed

100KΩ or this will circumvent the scintillation and

degrade leakage.

4. Capacitance

• 0.1 µF to 1000 µF

Refer to part number tables for available capaci-

tance ratings and tolerances by series.

Capacitance is measured at 120 Hz, up to 1.0

volt rms maximum and up to 2.5 volts DC maximum, at

+25°C.DC bias causes only a small reduction in capaci-

tance, up to about 2% when full rated voltage is applied.

DC bias is not commonly used at room temperature, but

is more commonly used at elevated temperatures.

Capacitance decreases with increasing frequency.

2. Operating Temperature Range

• –55 °C to +125 °C

Voltage derating is specified in Section 5.

Performance characteristics over this temperature

range are presented within the following sections.

3. Non-Operating Temperature Range

• –55 °C to +125 °C

Tantalum capacitors do not lose capacitance from

the “de-forming” effect as do liquid-electrolytic

capacitors. Storage at high temperature may

cause a small, temporary increase in leakage cur-

rent (measured under standard conditions), but the

original value is usually restored within a few min-

utes after application of rated voltage.

Tantalum chips are not hermetically sealed, there-

fore they do exhibit reversible changes in parame-

ters with respect to relative humidity (RH).

Capacitance increases with increasing humidity.

The limiting change, reached upon establishment

FIGURE 1 Typical Effect of Frequency upon Capacitance

Capacitance increases with increasing temperature.

+20%

+10%

0

-10%

-20%

FIGURE 2

-80 -60 -40 -20 0 +20 +40 +60 +80 +100 +120

Operating Temperature—ЊC

Typical Effect of Temperature upon Capacitance

©KEMET Electronics Corporation, P.O. Box 5928, Greenville, S.C. 29606, (864) 963-6300

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