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.
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,
suitable for resonant circuit application or other appli-
cations where high Q and stability of capacitance char-
acteristics are required. Class I capacitors have
II capacitors except for temperature characteristics,
which are greater than ± 15%. Class III capacitors
have the highest volumetric efficiency and poorest
stability of any type.
predictable temperature coefficients and are not
effected 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
or coupling applications or frequency discriminating
circuits where Q and stability of capacitance char-
acteristics are not of major importance. Class II
capacitors have temperature characteristics of ± 15%
or less. They are made from materials which are
X7R: Class II, with a maximum capacitance
change of ± 15% over an operating temperature
range of - 55°C to + 125°C.
Z5U: Class III, with a maximum capacitance
change of + 22% - 56% over an operating tem-
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
Dissipation Factor: Measured at following conditions:
C0G — 1 kHz and 1 vrms if capacitance > 1000 pF
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
Dielectric Strength: 2.5 times rated DC voltage.
Insulation Resistance (IR): At rated DC voltage,
whichever of the two is smaller
Temperature Characteristics: Range, °C
Capacitance Change without
* 1 MHz and 1 vrms if capacitance ≤ 100 pF on military product.
Pass Subsequent IR Test
or 100 GΩ
or 100 GΩ
or 10 GΩ
-55 to +125
0 ± 30 ppm/°C
-55 to +125
+10 to +85
© KEMET Electronics Corporation, P.O. Box 5928, Greenville, S.C. 29606, (864) 963-6300