TAP TEP Tech Summary and Application Guidelines

Section 3: Introduction
Foreword
AVX offers a broad line of solid Tantalum capacitors in a wide
range of sizes, styles, and ratings to meet any design needs.
This catalog combines into one source AVX’s leaded tantalum capacitor information from its worldwide tantalum operations.
The TAP/TEP is rated for use from -55°C to +85°C at rated
voltage and up to +125°C with voltage derating. There
are three preferred wire forms to choose from which are
available on tape and reel, and in bulk for hand insertion.
AVX has a complete tantalum applications service available
for use by all our customers. With the capability to prototype
and mass produce solid tantalum capacitors in special
configurations, almost any design need can be fulfilled.
And if the customer requirements are outside our standard
testing, AVX will work with you to define and implement a test
or screening plan.
AVX is determined to become the world leader in tantalum
capacitor technology and has made, and is continuing to
make, significant investments in equipment and research to
reach that end. We believe that the investment has paid off
with the devices shown on the following pages.
Dipped Radial Capacitors
SOLID TANTALUM RESIN DIPPED
SERIES TAP/TEP
The TAP/TEP resin dipped series of miniature tantalum
capacitors is available for individual needs in both commercial
and professional applications. From computers to automotive
to industrial, AVX has a dipped radial for almost any application.
Tantalum
Graphite
Resin encapsulation
Tantalum wire
Terminal Wire
Silver
Solder
Manganese
dioxide
Tantalum
pentoxide
JANUARY 2014
■ 133
Dipped Radial Capacitors
Wire Form Outline
SOLID TANTALUM RESIN DIPPED TAP/TEP
Preferred Wire Forms
D
Figure 1
D
Figure 2
D
Figure 3
H
H1 + 4 (0.16)
max
+
2.0(0.08)
max
H1
+
L
L
S
L
S
S
d
d
2.0 (0.079)
min
Wire Form C
2 (0.079)
min
d
Wire Form B
Wire Form S
Non-Preferred Wire Forms (Not recommended for new designs)
Figure 4
Figure 5
D
Figure 6
D
D
H1 max
+0.118
(3.0)
H + 3.8 (0.15)
max
+
0.079 (2)
min
L
1.10 +0.25
-0.10
L
L
S
(0.4 +0.010
-0.004 )
H
S
d
d
S
Wire Form F
Wire Form D
Wire Form G
DIMENSIONS
Wire Form
Figure
millimeters (inches)
Case Size
L (see note 1)
S
d
Packaging
Suffixes Available*
Preferred Wire Forms
C
Figure 1
A - R*
16.0±4.00
(0.630±0.160)
5.00±1.00
(0.200±0.040)
0.50±0.05
(0.020±0.002)
CCS
CRW
CRS
Bulk
Tape/Reel
Tape/Ammo
B
Figure 2
A - J*
16.0±4.00
(0.630±0.160)
5.00±1.00
(0.200±0.040)
0.50±0.05
(0.020±0.002)
BRW
BRS
Tape/Reel
Tape/Ammo
S
Figure 3
A - J*
16.0±4.00
(0.630±0.160)
2.50±0.50
(0.100±0.020)
0.50±0.05
(0.020±0.002)
SCS
SRW
SRS
Bulk
Tape/Reel
Tape/Ammo
Non-Preferred Wire Forms (Not recommended for new designs)
F
Figure 4
A-R
3.90±0.75
(0.155±0.030)
5.00±0.50
(0.200±0.020)
0.50±0.05
(0.020±0.002)
FCS
Bulk
D
Figure 5
A - H*
16.0±4.00
(0.630±0.160)
2.50±0.75
(0.100±0.020)
0.50±0.05
(0.020±0.002)
DCS
DTW
DTS
Bulk
Tape/Reel
Tape/Ammo
G
Figure 6
A-J
A-R
0.50±0.05
(0.020±0.002)
0.50±0.05
(0.020±0.002)
Bulk
Similar to
Figure 1
3.18±0.50
(0.125±0.020)
6.35±1.00
(0.250±0.040)
GSB
H
16.0±4.00
(0.630±0.160)
16.0±4.00
(0.630±0.160)
HSB
Bulk
Notes: (1) Lead lengths can be supplied to tolerances other than those above and should be specified in the ordering information.
(2) For D, H, and H1 dimensions, refer to individual product on following pages.
* For case size availability in tape and reel, please refer to pages 141-142.
134 ■ JANUARY 2014
TAP/TEP Technical Summary and
Application Guidelines
SECTION 1:
ELECTRICAL CHARACTERISTICS AND EXPLANATION OF TERMS
1.1 CAPACITANCE
1.1.1 Rated capacitance (CR)
This is the nominal rated capacitance. For tantalum capacitors it is measured as the capacitance of the equivalent
series circuit at 20°C in a measuring bridge supplied by a
120 Hz source free of harmonics with 2.2V DC bias max.
1.1.2 Temperature dependence on the capacitance
The capacitance of a tantalum capacitor varies with temperature. This variation itself is dependent to a small extent on
the rated voltage and capacitor size. See graph below for
typical capacitance changes with temperature.
1.1.3 Capacitance tolerance
This is the permissible variation of the actual value of the
capacitance from the rated value.
1.1.4 Frequency dependence of the capacitance
The effective capacitance decreases as frequency increases.
Beyond 100 kHz the capacitance continues to drop until resonance is reached (typically between 0.5-5 MHz depending
on the rating). Beyond this the device becomes inductive.
Typical Curve Capacitance vs. Frequency
Typical Capacitance vs. Temperature
1.4
15
1.2
5
CAP (␮F)
% Capacitance
10
0
-5
1.0
1.0␮F 35V
0.8
-10
0.6
-15
0.4
100Hz
-55
-25
0
25
50
75
100
1kHz
100kHz
10kHz
Frequency
125
Temperature (°C)
1.2 VOLTAGE
170 ■ JANUARY 2014
Category Voltage vs. Temperature
100
Percent of 85°C RVDC1 (VR)
1.2.1 Rated DC voltage (VR)
This is the rated DC voltage for continuous operation up to
+85°C.
1.2.2 Category voltage (VC)
This is the maximum voltage that may be applied continuously to a capacitor. It is equal to the rated voltage up to
+85°C, beyond which it is subject to a linear derating, to 2/3
VR at 125°C.
1.2.3 Surge voltage (VS)
This is the highest voltage that may be applied to a capacitor for short periods of time. The surge voltage may be
applied up to 10 times in an hour for periods of up to
30 seconds at a time. The surge voltage must not be used
as a parameter in the design of circuits in which, in the
normal course of operation, the capacitor is periodically
charged and discharged.
90
80
70
60
50
75
85
95
105
Temperature °C
115
125
TAP/TEP Technical Summary and
Application Guidelines
85°C
Rated
Voltage
(V DC)
2
3
4
6.3
10
16
20
25
35
50
125°C
Surge
Voltage
(V DC)
2.6
4
5.2
8
13
20
26
33
46
65
Category
Voltage
(V DC)
1.3
2
2.6
4
6.3
10
13
16
23
33
Surge
Voltage
(V DC)
1.7
2.6
3.4
5
9
12
16
21
28
40
1.2.4 Effect of surges
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.
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 situations it will be necessary to use a higher voltage rating.
1.2.5 Reverse voltage and non-polar operation
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.
The peak reverse voltage applied to the capacitor must not
exceed:
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
1% of category DC working voltage to a maximum of
0.1V at 125°C
1.2.6 Non-polar operation
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.
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.
1.2.8 Voltage derating
Refer to section 3.2 (pages 175-177) for the effect of voltage
derating on reliability.
1.3 DISSIPATION FACTOR AND TANGENT OF LOSS ANGLE (TAN D)
1.3.3 Frequency dependence of dissipation factor
Dissipation Factor increases with frequency as shown in the
typical curves below.
Typical Curve-Dissipation Factor vs. Frequency
100
V
50
3␮
10
V
F
10
3.
␮F
25
V
20
DF%
1.3.1 Dissipation factor (DF)
Dissipation factor is the measurement of the tangent of the
loss angle (Tan ␦) expressed as a percentage.
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.
1.3.2 Tangent of loss angle (Tan ␦)
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 measurement of Tan ␦ is carried out at +20°C and 120 Hz with 2.2V
DC bias max. with an AC voltage free of harmonics.
␮F
35
0
1.
10
5
2
1
100Hz
10kHz
1kHz
100kHz
Frequency
JANUARY 2014
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TAP/TEP Technical Summary and
Application Guidelines
1.3.4 Temperature dependence of dissipation factor
Typical Curves-Dissipation Factor vs. Temperature
Dissipation factor varies with temperature as the typical
curves show to the right. For maximum limits please refer to
ratings tables.
10
DF %
100␮F/6V
5
1␮F/35V
0
-55 -40 -20
0 20 40 60 80 100 125
Temperature C
1.4 IMPEDANCE, (Z) AND EQUIVALENT SERIES RESISTANCE (ESR)
172 ■ JANUARY 2014
1.4.3 Frequency dependence of impedance and ESR
ESR and impedance both increase with decreasing frequency.
At lower frequencies the values diverge as the extra contributions to impedance (resistance of the semiconducting
layer, etc.) become more significant. Beyond 1 MHz (and
beyond the resonant point of the capacitor) impedance again
increases due to induction.
Frequency Dependence of Impedance and ESR
1k
100
0.1 μF
10
ESR (␦)
1.4.1 Impedance, Z
This is the ratio of voltage to current at a specified frequency.
Three factors contribute to the impedance of a tantalum
capacitor; the resistance of the semiconducting layer,
the capacitance, and the inductance of the electrodes and
leads.
At high frequencies the inductance of the leads becomes a
limiting factor. The temperature and frequency behavior of
these three factors of impedance determine the behavior of
the impedance Z. The impedance is measured at 25°C and
100 kHz.
1.4.2 Equivalent series resistance, ESR
Resistance losses occur in all practical forms of capacitors.
These are made up from several different mechanisms,
including resistance in components and contacts, viscous
forces within the dielectric, and defects producing bypass
current paths. To express the effect of these losses they are
considered as the ESR of the capacitor. The ESR is frequency
dependent. The ESR can be found by using the relationship:
ESR = Tan ␦
2πfC
where f is the frequency in Hz, and C is the capacitance in
farads. The ESR is measured at 25°C and 100 kHz.
ESR is one of the contributing factors to impedance, and at
high frequencies (100 kHz and above) is the dominant factor,
so that ESR and impedance become almost identical,
impedance being marginally higher.
0.33 μF
1 μF
1
10 μF
0.1
33 μF
100 μF
0.01
100
10k
Frequency f (Hz)
Impedance (Z)
ESR
1k
100k
330 μF
1M
TAP/TEP Technical Summary and
Application Guidelines
Temperature Dependence of the
Impedance and ESR
100
ESR/Impedance Z (⍀)
1.4.4 Temperature dependence of the impedance and ESR
At 100 kHz, impedance and ESR behave identically and
decrease with increasing temperature as the typical curves
show. For maximum limits at high and low temperatures,
please refer to graph opposite.
1/35
10
10/35
1
47/35
x V volts
V max = 1- (T-85)
120
R
where T is the required operating temperature. Maximum
limits are given in rating tables.
1.5.3 Voltage dependence of the leakage current
The leakage current drops rapidly below the value corresponding to the rated voltage VR when reduced voltages are
applied. The effect of voltage derating on the leakage
current is shown in the graph.
This will also give a significant increase in reliability for any
application. See Section 3 (pages 175-177) for details.
1.5.4 Ripple current
The maximum ripple current allowance can be calculated from
the power dissipation limits for a given temperature rise above
ambient. Please refer to Section 2 (page 174) for details.
0
-20
+20 +40 +60
Temperature T (C)
+80 +100 +125
Temperature Dependence of the
Leakage Current for a Typical Component
10
1
0.1
-55 -40 -20
0 20 40 60
Temperature °C
80 100 125
Effect of Voltage Derating on Leakage Current
1
Leakage Current Ratio DCL/DCL @ VR
1.5.1 Leakage current (DCL)
The leakage current is dependent on the voltage applied, the
time, and the capacitor temperature. It is measured
at +25°C with the rated voltage applied. A protective resistance of 1000⍀ is connected in series with the capacitor
in the measuring circuit.
Three minutes after application of the rated voltage the leakage current must not exceed the maximum values indicated
in the ratings table. Reforming is unnecessary even after prolonged periods without the application of voltage.
1.5.2 Temperature dependence of the leakage current
The leakage current increases with higher temperatures, typical
values are shown in the graph.
For operation between 85°C and 125°C, the maximum
working voltage must be derated and can be found from the
following formula.
0.1
-55 -40
Leakage Current DCLT/DCL 25°C
1.5 DC LEAKAGE CURRENT (DCL)
E
NG
L
CA
PI
TY
RA
0.1
0.01
0
20 40
60
80 100
% of Rated Voltage (VR)
JANUARY 2014
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TAP/TEP Technical Summary and
Application Guidelines
SECTION 2:
AC OPERATION — RIPPLE VOLTAGE AND RIPPLE CURRENT
2.1 RIPPLE RATINGS (AC)
In an AC application heat is generated within the capacitor
by both the AC component of the signal (which will depend
upon signal form, amplitude and frequency), and by the
DC leakage. For practical purposes the second factor is
insignificant. The actual power dissipated in the capacitor is
calculated using the formula:
2
R
P = I2 R = E 2
Z
I = rms ripple current, amperes
R = equivalent series resistance, ohms
E = rms ripple voltage, volts
P = power dissipated, watts
Z = impedance, ohms, at frequency under
consideration
Using this formula it is possible to calculate the maximum
AC ripple current and voltage permissible for a particular
application.
2.2 MAXIMUM AC RIPPLE VOLTAGE
(EMAX)
From the previous equation:
E (max) = Z
P max
R
where Pmax is the maximum permissible ripple voltage as listed
for the product under consideration (see table).
However, care must be taken to ensure that:
1. The DC working voltage of the capacitor must not be
exceeded by the sum of the positive peak of the applied
AC voltage and the DC bias voltage.
2. The sum of the applied DC bias voltage and the negative
peak of the AC voltage must not allow a voltage reversal
in excess of that defined in the sector, ‘Reverse Voltage’.
2.3 MAXIMUM PERMISSIBLE POWER
DISSIPATION (WATTS) @ 25°C
The maximum power dissipation at 25°C has been calculated
for the various series and are shown in Section 2.4, together
with temperature derating factors up to 125°C.
For leaded components the values are calculated for parts
supported in air by their leads (free space dissipation).
The ripple ratings are set by defining the maximum temperature rise to be allowed under worst case conditions, i.e.,
with resistive losses at their maximum limit. This differential
is normally 10°C at room temperature dropping to 2°C at
125°C. In application circuit layout, thermal management,
available ventilation, and signal waveform may significantly
174 ■ JANUARY 2014
affect the values quoted below. It is recommended that
temperature measurements are made on devices during
operating conditions to ensure that the temperature differential
between the device and the ambient temperature is less than
10°C up to 85°C and less than 2°C between 85°C and 125°C.
Derating factors for temperatures above 25°C are also shown
below. The maximum permissible proven dissipation should be
multiplied by the appropriate derating factor.
For certain applications, e.g., power supply filtering, it may
be desirable to obtain a screened level of ESR to enable
higher ripple currents to be handled. Please contact our
applications desk for information.
2.4 POWER DISSIPATION RATINGS
(IN FREE AIR)
TAR – Molded Axial
Case
size
Q
R
S
W
Max. power
dissipation (W)
0.065
0.075
0.09
0.105
Temperature
derating factors
Temp. °C
Factor
+25
1.0
+85
0.6
+125
0.4
TAA – Hermetically Sealed Axial
Case
size
A
B
C
D
Max. power
dissipation (W)
0.09
0.10
0.125
0.18
Temperature
derating factors
Temp. °C
Factor
+20
1.0
+85
0.9
+125
0.4
TAP/TEP – Resin Dipped Radial
Case
size
Max. power
dissipation (W)
A
B
C
D
E
F
G
H
J
K
L
M/N
P
R
0.045
0.05
0.055
0.06
0.065
0.075
0.08
0.085
0.09
0.1
0.11
0.12
0.13
0.14
Temperature
derating factors
Temp. °C
Factor
+25
1.0
+85
0.4
+125
0.09
TAP/TEP Technical Summary and
Application Guidelines
SECTION 3:
RELIABILITY AND CALCULATION OF FAILURE RATE
3.1 STEADY-STATE
Infant
Mortalities
Voltage Correction Factor
1.0000
Correction Factor
Tantalum Dielectric has essentially no wear out mechanism
and in certain circumstances is capable of limited self
healing, random failures can occur in operation. The failure
rate of Tantalum capacitors will decrease with time and not
increase as with other electrolytic capacitors and other
electronic components.
0.1000
0.0100
0.0010
0.0001
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
Applied Voltage / Rated Voltage
Figure 2. Correction factor to failure rate F for voltage
derating of a typical component (60% con. level).
Useful life reliability can be altered by voltage
derating, temperature or series resistance
Figure 1. Tantalum reliability curve.
The useful life reliability of the Tantalum capacitor is affected
by three factors. The equation from which the failure rate can
be calculated is:
F = FU x FT x FR x FB
where FU is a correction factor due to operating voltage/
voltage derating
FT is a correction factor due to operating
temperature
FR is a correction factor due to circuit series
resistance
FB is the basic failure rate level. For standard
leaded Tantalum product this is 1%/1000hours
Operating voltage/voltage derating
If a capacitor with a higher voltage rating than the maximum
line voltage is used, then the operating reliability will be
improved. This is known as voltage derating. The graph,
Figure 2, shows the relationship between voltage derating
(the ratio between applied and rated voltage) and the failure
rate. The graph gives the correction factor FU for any
operating voltage.
Operating temperature
If the operating temperature is below the rated temperature
for the capacitor then the operating reliability will be improved
as shown in Figure 3. This graph gives a correction factor FT
for any temperature of operation.
Temperature Correction Factor
100.0
Correction Factor
Infinite Useful Life
10.0
Tantalum
1.0
0.1
0.0
20
30
40
50 60
70 80 90 100 110 120 130
Temperature (C)
Figure 3. Correction factor to failure rate F for ambient
temperature T for typical component (60% con. level).
JANUARY 2014
■ 175
TAP/TEP Technical Summary and
Application Guidelines
Circuit Impedance
All solid tantalum capacitors require current limiting
resistance to protect the dielectric from surges. A series
resistor is recommended for this purpose. A lower circuit
impedance may cause an increase in failure rate, especially
at temperatures higher than 20°C. An inductive low impedance circuit may apply voltage surges to the capacitor and
similarly a non-inductive circuit may apply current surges
to the capacitor, causing localized over-heating and failure.
The recommended impedance is 1Ω per volt. Where this is
not feasible, equivalent voltage derating should be used
(See MIL HANDBOOK 217E). Table I shows the correction
factor, FR, for increasing series resistance.
Table I: Circuit Impedance
Correction factor to failure rate F for series resistance R
on basic failure rate FB for a typical component (60%
con. level).
Circuit Resistance ohms/volt
3.0
2.0
1.0
0.8
0.6
0.4
0.2
0.1
FR
0.07
0.1
0.2
0.3
0.4
0.6
0.8
1.0
Example calculation
Consider a 12 volt power line. The designer needs about
10μF of capacitance to act as a decoupling capacitor near a
video bandwidth amplifier. Thus the circuit impedance will be
limited only by the output impedance of the boards power
unit and the track resistance. Let us assume it to be about
2 Ohms minimum, i.e., 0.167 Ohms/Volt. The operating
temperature range is -25°C to +85°C. If a 10μF 16 Volt
capacitor was designed-in, the operating failure rate would
be as follows:
a) FT = 0.8 @ 85°C
b) FR = 0.7 @ 0.167 Ohms/Volt
c) FU = 0.17 @ applied voltage/rated voltage = 75%
Thus FB = 0.8 x 0.7 x 0.17 x 1 = 0.0952%/1000 Hours
If the capacitor was changed for a 20 volt capacitor, the
operating failure rate will change as shown.
FU = 0.05 @ applied voltage/rated voltage = 60%
FB = 0.8 x 0.7 x 0.05 x 1 = 0.028%/1000 Hours
176 ■ JANUARY 2014
3.2 DYNAMIC
As stated in Section 1.2.4 (page 171), the solid Tantalum
capacitor has a limited ability to withstand voltage and current
surges. Such current surges can cause a capacitor to fail.
The expected failure rate cannot be calculated by a simple
formula as in the case of steady-state reliability. The two
parameters under the control of the circuit design engineer
known to reduce the incidence of failures are derating and
series resistance.The table below summarizes the results of
trials carried out at AVX with a piece of equipment which has
very low series resistance and applied no derating. So that
the capacitor was tested at its rated voltage.
Results of production scale derating experiment
Capacitance and Number of units 50% derating No derating
Voltage
tested
applied
applied
47μF 16V
1,547,587
0.03%
1.1%
100μF 10V
632,876
0.01%
0.5%
22μF 25V
2,256,258
0.05%
0.3%
As can clearly be seen from the results of this experiment,
the more derating applied by the user, the less likely the
probability of a surge failure occurring.
It must be remembered that these results were derived from
a highly accelerated surge test machine, and failure rates in
the low ppm are more likely with the end customer.
TAP/TEP Technical Summary and
Application Guidelines
A commonly held misconception is that the leakage current
of a Tantalum capacitor can predict the number of failures
which will be seen on a surge screen. This can be disproved
by the results of an experiment carried out at AVX on 47μF
10V surface mount capacitors with different leakage
currents. The results are summarized in the table below.
Leakage Current vs Number of Surge Failures
Standard leakage range
0.1 μA to 1μA
Over Catalog limit
5μA to 50μA
Classified Short Circuit
50μA to 500μA
Number tested
10,000
Number failed surge
25
10,000
26
10,000
25
Again, it must be remembered that these results were
derived from a highly accelerated surge test machine,
and failure rates in the low ppm are more likely with the end
customer.
AVX recommended derating table
Voltage Rail
Working Cap Voltage
3.3
6.3
5
10
10
20
12
25
15
35
≥24
Series Combinations (11)
For further details on surge in Tantalum capacitors refer
to J.A. Gill’s paper “Surge in Solid Tantalum Capacitors”,
available from AVX offices worldwide.
An added bonus of increasing the derating applied in a
circuit, to improve the ability of the capacitor to withstand
surge conditions, is that the steady-state reliability is
improved by up to an order. Consider the example of a
6.3 volt capacitor being used on a 5 volt rail. The steadystate reliability of a Tantalum capacitor is affected by three
parameters; temperature, series resistance and voltage
derating. Assuming 40°C operation and 0.1Ω/volt of series
resistance, the scaling factors for temperature and series
resistance will both be 0.05 [see Section 3.1 (page 174)]. The
derating factor will be 0.15. The capacitors reliability will
therefore be
Failure rate = FU x FT x FR x 1%/1000 hours
= 0.15 x 0.05 x 1 x 1%/1000 hours
= 7.5% x 10-3/hours
If a 10 volt capacitor was used instead, the new scaling factor
would be 0.017, thus the steady-state reliability would be
Failure rate = FU x FT x FR x 1%/1000 hours
= 0.017 x 0.05 x 1 x 1%/1000 hours
= 8.5% x 10-4/ 1000 hours
So there is an order improvement in the capacitors steadystate reliability.
3.3 RELIABILITY TESTING
AVX performs extensive life testing on tantalum capacitors.
■ 2,000 hour tests as part of our regular Quality Assurance
Program.
Test conditions:
■ 85°C/rated voltage/circuit impedance of 3Ω max.
■ 125°C/0.67 x rated voltage/circuit impedance of 3Ω max.
3.4 Mode of Failure
This is normally an increase in leakage current which ultimately
becomes a short circuit.
JANUARY 2014
■ 177
TAP/TEP Technical Summary and
Application Guidelines
SECTION 4:
APPLICATION GUIDELINES FOR TANTALUM CAPACITORS
4.1 SOLDERING CONDITIONS AND
BOARD ATTACHMENT
4.2 RECOMMENDED SOLDERING
PROFILES
The soldering temperature and time should be the minimum
for a good connection.
A suitable combination for wavesoldering is 230°C - 250°C
for 3 - 5 seconds.
Small parametric shifts may be noted immediately after wave
solder, components should be allowed to stabilize at room
temperature prior to electrical testing.
AVX leaded tantalum capacitors are designed for wave
soldering operations.
Recommended wave soldering profile for mounting of
tantalum capacitors is shown below.
After soldering the assembly should preferably be allowed to
cool naturally. In the event that assisted cooling is used, the
rate of change in temperature should not exceed that used
in reflow.
Allowable range of peak temp./time combination for wave soldering
270
260
Dangerous Range
250
Temperature 240
( o C)
230
Allowable Range
with Care
220
Allowable Range
with Preheat
210
200
0
2
4
6
8
Soldering Time (secs.)
10
12
*See appropriate product specification
SECTION 5:
MECHANICAL AND THERMAL PROPERTIES, LEADED CAPACITORS
5.1 ACCELERATION
5.6 SOLDERING CONDITIONS
10 g (981 m/s)
Dip soldering permissible provided solder bath temperature
⬉270°C; solder time <3 sec.; circuit board thickness
⭌1.0 mm.
5.2 VIBRATION SEVERITY
10 to 2000 Hz, 0.75 mm or 98 m/s2
5.7 INSTALLATION INSTRUCTIONS
5.3 SHOCK
The upper temperature limit (maximum capacitor surface
temperature) must not be exceeded even under the most
unfavorable conditions when the capacitor is installed. This
must be considered particularly when it is positioned near
components which radiate heat strongly (e.g., valves and
power transistors). Furthermore, care must be taken, when
bending the wires, that the bending forces do not strain the
capacitor housing.
Trapezoidal Pulse 10 g (981 m/s) for 6 ms
5.4 TENSILE STRENGTH OF
CONNECTION
10 N for type TAR, 5 N for type TAP/TEP.
5.5 BENDING STRENGTH OF
CONNECTIONS
2 bends at 90°C with 50% of the tensile strength test loading.
5.8 INSTALLATION POSITION
No restriction.
5.9 SOLDERING INSTRUCTIONS
Fluxes containing acids must not be used.
178 ■ JANUARY 2014