General Description
Table 1: EIA and MIL Temperature Stable and General
Application Codes
EIA CODE
Percent Capacity Change Over Temperature Range
RS198
X7
X5
Y5
Z5
Code
D
E
F
P
R
S
T
U
V
Temperature Range
-55°C to +125°C
-55°C to +85°C
-30°C to +85°C
+10°C to +85°C
Percent Capacity Change
Capacitance Change Percent
Effects of Voltage –
Variations in voltage have little effect
on Class 1 dielectric but does affect the capacitance and
dissipation factor of Class 2 dielectrics. The application of
DC voltage reduces both the capacitance and dissipation
factor while the application of an AC voltage within a
reasonable range tends to increase both capacitance and
dissipation factor readings. If a high enough AC voltage is
applied, eventually it will reduce capacitance just as a DC
voltage will. Figure 2 shows the effects of AC voltage.
Cap. Change vs. A.C. Volts
X7R
50
40
30
20
10
0
12.5
25
37.5
Volts AC at 1.0 KHz
50
±3.3%
±4.7%
±7.5%
±10%
±15%
±22%
+22%, -33%
+22%, - 56%
+22%, -82%
EXAMPLE – A capacitor is desired with the capacitance value at 25°C
to increase no more than 7.5% or decrease no more than 7.5% from
-30°C to +85°C. EIA Code will be Y5F.
Figure 2
MIL CODE
Symbol
A
B
C
Symbol
Q
R
W
X
Y
Z
Temperature Range
-55°C to +85°C
-55°C to +125°C
-55°C to +150°C
Capacitor specifications specify the AC voltage at which to
measure (normally 0.5 or 1 VAC) and application of the
wrong voltage can cause spurious readings.
Typical Cap. Change vs. Temperature
X7R
Capacitance Change Percent
+20
+10
0VDC
0
-10
-20
-30
-55 -35
-15
+5
+25 +45 +65 +85 +105 +125
Cap. Change
Zero Volts
+15%, -15%
+15%, -15%
+22%, -56%
+15%, -15%
+30%, -70%
+20%, -20%
Cap. Change
Rated Volts
+15%, -50%
+15%, -40%
+22%, -66%
+15%, -25%
+30%, -80%
+20%, -30%
Temperature characteristic is specified by combining range and change
symbols, for example BR or AW. Specification slash sheets indicate the
characteristic applicable to a given style of capacitor.
In specifying capacitance change with temperature for Class
2 materials, EIA expresses the capacitance change over an
operating temperature range by a 3 symbol code. The
first symbol represents the cold temperature end of the
temperature range, the second represents the upper limit of
the operating temperature range and the third symbol repre-
sents the capacitance change allowed over the operating
temperature range. Table 1 provides a detailed explanation of
the EIA system.
Temperature Degrees Centigrade
Figure 3
61
AVX [ AVX CORPORATION ]
