4.Type of Applied Voltage and Self-heating Temperature
[Example of Temperature Rise (Heat Generation) in Chip
Multilayer Ceramic Capacitors in Contrast to Ripple Current]
Sample: R(R1) characteristics 10μF, Rated voltage: DC10V
1.Confirm the operating conditions to make sure that no large current is flowing into the capacitor due to the continuous
application of an AC voltage or pulse voltage.
When a DC rated voltage product is used in an AC voltage circuit or a pulse voltage circuit, the AC current or pulse
current will flow into the capacitor; therefore check the self-heating condition.
Please confirm the surface temperature of the capacitor so that the temperature remains within the upper limits
Ripple Current
100
ꢀof the operating temperature, including the rise in temperature due to self-heating.
When the capacitor is used with a high-frequency voltage or pulse voltage, heat may be generated by dielectric loss.
ꢀꢀ<Applicable to Rated Voltage of less than 100VDC>
10
ꢀꢀThe load should be contained so that the self-heating of the capacitor body remains below 20°C,
when measuring at an ambient temperature of 25°C.
100kHz
500kHz
1MHz
1
0
1
2
3
4
5
6
Current (Ar.m.s.)
5. DC Voltage and AC Voltage Characteristic
1. The capacitance value of a high dielectric constant type capacitor changes depending on the DC voltage applied.
Please consider the DC voltage characteristics when a capacitor is selected for use in a DC circuit.
[Example of DC Voltage Characteristics]
Sample: X7R(R7) Characteristics 0.1μF, Rated Voltage 50VDC
20
1-1. The capacitance of ceramic capacitors may change sharply depending on the applied voltage. (See figure)
Please confirm the following in order to secure the capacitance.
0
-20
-40
-60
-80
(1) Determine whether the capacitance change caused by the applied voltage is within the allowed range.
(2) In the DC voltage characteristics, the rate of capacitance change becomes larger as voltage increases,
even if the applied voltage is below the rated voltage.
When a high dielectric constant type capacitor is used in a circuit that requires a tight (narrow) capacitance
tolerance (e.g., a time constant circuit), please carefully consider the voltage characteristics, and confirm
the various characteristics in the actual operating conditions of the system.
-100
0
10
20
30
40
50
DC Voltage (V)
ꢀ2. The capacitance values of high dielectric constant type capacitors changes depending on the AC voltage applied.
[Example of AC Voltage Characteristics]
Sample: X7R(R7) Characteristics 10μF, Rated Voltage 6.3VDC
Please consider the AC voltage characteristics when selecting a capacitor to be used in a AC circuit.
30
20
10
0
-10
-20
-30
-40
-50
-60
0
0.5
1
1.5
2
AC Voltage (Vr.m.s.)
GRM1857U1H302JA44-01A
MURATA [ muRata ]
