Datasheet
4. Impedauce(Z), and Equivalent Series Resistance(ESR)
4-1 Impedance(Z)
The impedance is measured at 25℃ and 100KHZ.
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 semiconductor layer; the capacitance value
and the inductance of the electrode and leads. at high frequencies
the inductance of leads becomes a limiting factor.
Total impedance of the capacitor is the vector sum of capacitive
reactance(Xc) and ESR, below resonance; above resonance total
impedance is the vector sum of inductive reactance(XL) and ESR
(Figure 5 and 6).
Typical impedance versus frequency curve is shown in Figure.
4-2. Equivalent Series Resistance (ESR)
The ESR is measured at 25℃ and 100KHZ.
Resistance losses occur in all practical forms capacitors.
Equivalent Series Resistance (ESR) is the preferred high-frequency
statement of the resistance unavoidably appearing in these
capacitors. ESR is not a pure resistance, and it decreases with
increasing frequency.
The ESR is frequency dependent and can be found by using the
relationship;
ESR = tan δ/ 2πfC
ESR is the contributing factors to impedance, and at high frequen-
cies (100KHZ and above) It becomes the dominant factor.
1.8
1.7
1.6
1.5
1.4
1.3
1.2
1.1
1
0.9
0.8
-55 -5 45 95
Temperature(Celcius)
DF Multiplier
TYPICAL DF VS TEMPERATURE
100
10
1
0.1
0.1 1 10 100 1000
Frequency(kHz)
Impedance Multiplier
TYPICAL IMPEDANCE VS FREQUENCY
5
4.5
4
3.5
3
2.5
2
1.5
1
0.5
0
0.1 1 10 100 1000
Frequency(kHz)
ESR Multiplier
TYPICAL ESR VS FREQUENCY
100
10
1
0.1
0.1 1 10 100 1000
Frequency(kHz)
Impedance Multiplier
TYPICAL ESR VS FREQUENCY
Total impedance of the Capacitor above Resonance
ESR
X
C
=
R
2πf
C
ohm
where:
f
=
frequency, Hertz
C
=
capacitance, Farad
Ø
δ
X
C
Z
Total impedance of the Capacitor above Resonance
ESR
XL=2πf
L
where:
f
=
frequency, Hertz
L
=
inductance, Henries
Ø
δ
X
C
Z
5.
Impedance(Z) & ESR
10
11
Precautions in using
Tantalum Capacitors
4 Characteristics
Explanation
SCN Series
SCS Series
SCS-P Series
SCM Series
SCF Series
SCE Series
Taping
Specification
Marking
Specification
SCL Series
PCS Series
PCL Series