The Capacitor
Impedance vs. Frequency
Effect of Capacitance – AVX SpinGuards
Typical Curve of Aging Rate
X7R Dielectric
+1.5
0
10.00
1.00
0.10
0.01
.001mF
-1.5
.01mF
-3.0
-4.5
.1mF
.33mF
1
10
100
1000
Log Frequency, MHz
-6.0
-7.5
1
10
100 1000 10,000 100,000
Hours
Impedance vs. Frequency
Effect of Dielectric – AVX DIPGuards
Characteristic Max. Aging Rate %/Decade
None
C0G (NP0)
X7R
Z5U
2
3
5
10.0
Figure 9
Y5V
Effects of Mechanical Stress – High “K” dielectric ceramic
capacitors exhibit some low level piezoelectric reactions
under mechanical stress. As a general statement, the
piezoelectric output is higher, the higher the dielectric con-
stant of the ceramic. It is desirable to investigate this effect
before using high “K” dielectrics as coupling capacitors in
extremely low level applications.
1.0
0.1
Reliability – Historically ceramic capacitors have been one
of the most reliable types of capacitors in use today.
The approximate formula for the reliability of a ceramic
capacitor is:
1
10
100
200
Log Frequency, MHz
Lo
Lt
Vt
X
Tt
Y
=
͑ ͑
͑ ͑
V
T
o
o
Impedance vs. Frequency
Effect of Lead Length – Military CKR05 .01mF
where
100.0
Lo = operating life
Lt = test life
Tt = test temperature and
.500"
.250"
.062"
0"
To = operating temperature in °C
Vt = test voltage
Vo = operating voltage X,Y = see text
10.0
1.0
Historically for ceramic capacitors exponent X has been
considered as 3. The exponent Y for temperature effects
typically tends to run about 8.
0.1
1
10
100
1000
Log Frequency, MHz
Figure 8
7
KYOCERA AVX [ KYOCERA AVX ]
