TAP/TEP Technical Summary and
Application Guidelines
1.2.5 Reverse voltage and non-polar operation
85°C
125°C
The reverse voltage ratings are designed to cover exceptional
conditions of small level excursions into incorrect polarity.
The values quoted are not intended to cover continuous
reverse operation.
Rated
Voltage
(V DC)
Surge
Voltage
(V DC)
Category
Voltage
(V DC)
Surge
Voltage
(V DC)
2
3
4
6.3
10
16
20
25
35
50
2.6
4
5.2
8
13
20
26
33
46
65
1.3
2
2.6
4
6.3
10
13
16
23
33
1.7
2.6
3.4
5
The peak reverse voltage applied to the capacitor must not
exceed:
9
10% of rated DC working voltage to a maximum of
1V at 25°C
3% of rated DC working voltage to a maximum of
0.5V at 85°C
12
16
21
28
40
1% of category DC working voltage to a maximum of
0.1V at 125°C
1.2.6 Non-polar operation
1.2.4 Effect of surges
If the higher reverse voltages are essential, then two capacitors,
each of twice the required capacitance and of equal
tolerance and rated voltage, should be connected in a
back-to-back configuration, i.e., both anodes or both
cathodes joined together. This is necessary in order to avoid
a reduction in life expectancy.
The solid Tantalum capacitor has a limited ability to withstand
surges (15% to 30% of rated voltage). This is in common
with all other electrolytic capacitors and is due to the fact that
they operate under very high electrical stress within the oxide
layer. In the case of ‘solid’ electrolytic capacitors this is further
complicated by the limited self healing ability of the manganese
dioxide semiconductor.
1.2.7 Superimposed AC voltage (Vrms) - Ripple Voltage
This is the maximum RMS alternating voltage, superimposed
on a DC voltage, that may be applied to a capacitor. The
sum of the DC voltage and the surge value of the
superimposed AC voltage must not exceed the category
voltage, Vc. Full details are given in Section 2.
It is important to ensure that the voltage across the terminals of
the capacitor does not exceed the surge voltage rating at any
time. This is particularly so in low impedance circuits where the
capacitor is likely to be subjected to the full impact of surges,
especially in low inductance applications. Even an extremely
short duration spike is likely to cause damage. In such situa-
tions it will be necessary to use a higher voltage rating.
1.2.8 Voltage derating
Refer to section 3.2 (pages 155-157) for the effect of voltage
derating on reliability.
1.3 DISSIPATION FACTOR AND TANGENT OF LOSS ANGLE (TAN D)
1.3.1 Dissipation factor (DF)
1.3.3 Frequency dependence of dissipation factor
Dissipation factor is the measurement of the tangent of the
loss angle (Tan ␦) expressed as a percentage.
Dissipation Factor increases with frequency as shown in the
typical curves below.
The measurement of DF is carried out at +25°C and 120 Hz
with 2.2V DC bias max. with an AC voltage free of harmonics.
The value of DF is temperature and frequency dependent.
Typical Curve-Dissipation Factor vs. Frequency
100
1.3.2 Tangent of loss angle (Tan ␦)
50
20
This is a measure of the energy loss in the capacitor. It is
expressed as Tan ␦ and is the power loss of the capacitor
divided by its reactive power at a sinusoidal voltage of specified
frequency. (Terms also used are power factor, loss factor and
dielectric loss, Cos (90 - ␦) is the true power factor.) The meas-
urement of Tan ␦ is carried out at +20°C and 120 Hz with 2.2V
DC bias max. with an AC voltage free of harmonics.
10
5
2
1
100kHz
100Hz
10kHz
1kHz
Frequency
MAY 2013 ■ 151
KYOCERA AVX [ KYOCERA AVX ]
