MULTILAYER CERAMIC CAPACITORS/AXIAL
& RADIAL LEADED
Multilayer ceramic capacitors are available in a
variety of physical sizes and configurations, including
leaded devices and surface mounted chips. Leaded
styles include molded and conformally coated parts
with axial and radial leads. However, the basic
capacitor element is similar for all styles. It is called a
chip and consists of formulated dielectric materials
which have been cast into thin layers, interspersed
with metal electrodes alternately exposed on opposite
edges of the laminated structure. The entire structure is
fired at high temperature to produce a monolithic
block which provides high capacitance values in a
small physical volume. After firing, conductive
terminations are applied to opposite ends of the chip to
make contact with the exposed electrodes.
Termination materials and methods vary depending on
the intended use.
TEMPERATURE CHARACTERISTICS
Ceramic dielectric materials can be formulated with
Class III: General purpose capacitors, suitable
a wide range of characteristics. The EIA standard for
for by-pass coupling or other applications in which
ceramic dielectric capacitors (RS-198) divides ceramic
dielectric losses, high insulation resistance and
dielectrics into the following classes:
stability of capacitance characteristics are of little or
no importance. Class III capacitors are similar to Class
Class I: Temperature compensating capacitors,
II capacitors except for temperature characteristics,
suitable for resonant circuit application or other appliwhich are greater than ± 15%. Class III capacitors
cations where high Q and stability of capacitance charhave the highest volumetric efficiency and poorest
acteristics are required. Class I capacitors have
stability of any type.
predictable temperature coefficients and are not
affected by voltage, frequency or time. They are made
KEMET leaded ceramic capacitors are offered in
from materials which are not ferro-electric, yielding
the three most popular temperature characteristics:
superior stability but low volumetric efficiency. Class I
C0G: Class I, with a temperature coefficient of 0 ±
capacitors are the most stable type available, but have
30 ppm per degree C over an operating
the lowest volumetric efficiency.
temperature range of - 55°C to + 125°C (Also
known as “NP0”).
Class II: Stable capacitors, suitable for bypass
X7R: Class II, with a maximum capacitance
or coupling applications or frequency discriminating
change of ± 15% over an operating temperature
circuits where Q and stability of capacitance charrange of - 55°C to + 125°C.
acteristics are not of major importance. Class II
Z5U: Class III, with a maximum capacitance
capacitors have temperature characteristics of ± 15%
change of + 22% - 56% over an operating temor less. They are made from materials which are
perature range of + 10°C to + 85°C.
ferro-electric, yielding higher volumetric efficiency but
less stability. Class II capacitors are affected by
Specified electrical limits for these three temperature
temperature, voltage, frequency and time.
characteristics are shown in Table 1.
SPECIFIED ELECTRICAL LIMITS
Temperature Characteristics
Parameter
C0G
Z5U
0.10%
Dissipation Factor: Measured at following conditions.
C0G – 1 kHz and 1 vrms if capacitance >1000pF
1 MHz and 1 vrms if capacitance 1000 pF
X7R – 1 kHz and 1 vrms* or if extended cap range 0.5 vrms
Z5U – 1 kHz and 0.5 vrms
X7R
2.5%
(3.5% @ 25V)
4.0%
Dielectric Stength: 2.5 times rated DC voltage.
Pass Subsequent IR Test
Insulation Resistance (IR): At rated DC voltage,
whichever of the two is smaller
1,000 M
F
or 100 G
1,000 M
F
or 100 G
Temperature Characteristics: Range, °C
Capacitance Change without
DC voltage
-55 to +125
0 ± 30 ppm/°C
-55 to +125
± 15%
* MHz and 1 vrms if capacitance
1,000 M
or 10 G
100 pF on military product.
Table I
4
© KEMET Electronics Corporation, P.O. Box 5928, Greenville, S.C. 29606, (864) 963-6300
F
+ 10 to +85
+22%,-56%
