T192A256M008ASC Datasheet, PDF (3/28 Pages) Kemet Corporation – Wet Tantalum General Information

Performance Characteristics
Introduction
KEMET wet tantalum capacitors are identified by
the initial “T”, followed by a “Series” number. T19X des-
ignates commercial product; T29X is military grade in
accordance with Military Specification, MIL-PRF-
39006. For detailed performance characteristics of the
T29X series, please refer to the latest issue of the
Military Specification. MIL-PRF-39006 establishes
1000 hour failure rate levels of 1%, 0.1%, and 0.01%.
T29X series components are available in M, P, and R
failure rates (1.0, 0.1, and 0.01, respectively).
Specific requirements are set forth in the respec-
tive Product Series in this catalog. All Military products
are 100% electrically screened for the parameters
shown in the respective product section. For non-mili-
tary product, all series are 100% screened for leakage,
capacitance and dissipation factor. All Series are
inspected to electrical limits using a minimum .1% AQL
sampling plans, 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
similar products. KEMET capacitors may also be sup-
plied, with prior agreement, to meet specifications with
requirements differing from those of KEMET catalogs.
These Notes apply generally to all KEMET wet tan-
talum capacitors and illustrate typical performance
under normal application conditions, except where
noted. The intent of these Notes is to provide general-
ized information concerning performance characteris-
tics.
1. General Application Class
Wet tantalum capacitors are usually applied in cir-
cuits where the AC component is small compared to
the DC component. Typical uses known to KEMET
Electronics include blocking, by-passing, decoupling,
and filtering. They are also used in timing circuits. If two
of these polar capacitors are connected “back-to-back”
(i.e., negative-to-negative or positive-to-positive), the
pair may be used in AC applications (as a non-polar
device).
2. Storage Conditions
Capacitors may be stored without applied voltage
over the operating temperature range specified in the
catalogs for each Series. The range is from -55 to
+125°C for all Series.
Storage at high temperature may cause a small,
temporary increase in leakage current (measured
under standard conditions), but the original value is
usually restored within a few minutes after application
of rated voltage.
DC leakage current may rise upon exposure to a
combination of high temperature and high humidity, 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.
This Series 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 parameter is leakage current.
3. Polarity
These capacitors are inherently polar devices and
may be permanently damaged or destroyed if connect-
ed with the wrong polarity. The positive terminal is iden-
tified on the capacitor body by a polarity mark and the
capacitor body may include an obvious geometrical
shape. See paragraph 11 for Reverse Voltage capabil-
ities.
4. Operating Environment
Most of the discussion under “Storage Conditions”
will apply also when capacitors are operated within the
applicable electrical ratings described below. The tem-
porary increase in leakage current (at standard condi-
tions) following elevated-temperature exposure is not
observed, however, if the capacitors are operated with
adequate DC voltage applied.
5. Capacitance
Capacitance is measured at 120 Hz and 25°C with
up to 1 volt rms applied. Measured circuits are of high
impedance, however, and under these conditions 1 volt
rms may be applied even to 6 volt capacitors (23%
peak reversal) without a DC dias. DC bias is thus nor-
mally not used, except when rated voltage is below 6
volts and the AC signal level exceeds 0.3 vrms.
However, MIL-PRF-39006 provides for up to 2.2 volts
DC. DC bias is not commonly used at room tempera-
ture, but is more commonly used at elevated tempera-
tures.
DC bias causes a small reduction in capacitance,
up to about 2% when full rated voltage is applied as
bias. DF is also reduced by the presence of DC.
Capacitance changes very little below 1 kHz but
decreases more noticably at higher frequencies. Larger
capacitance values decline more rapidly than small rat-
ings.
Capacitance typically changes with temperature
according to the curve of Figure 1.
Figure 1. Typical Effect of Temperature upon
Capacitance
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