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In this article i am explaining the differences between different Ceramic capactior dielectric materials like X7R, X5R, X8R, Z5U,Y5V, X7S, C0G. I used to encounter these names X7R and X5R capacitors regularly but never bothered to look at what they are. Recently i took some time to study them realised how important they are and here are the details of what i learnt.
Ceramic capacitors are broadly categorized into 4 classes based on the dielectrics used in them,
* Class 1 * Class 2 * Class 3 * Class 4
Class 3 and Class 4 capacitors are not widely used and hence have not been standardized.
* * *
Class 1 Capacitors :
Class 1 capacitors have following characteristics,
* _Linear temperature coefficient :_ Their capacitance varies linearly with temperature * _No Voltage dependency :_ Their capacitance does not depend on the applied voltage * _No Aging :_ They do not suffer significant aging process due to para electric materials used in manufacturing * _No electrical losses :_ Have significantly low electrical losses compared to Class 2 capacitors * _Used in High Q filters :_ Due to the above properties they are used in applications like resonant circuits, PLL and Oscillators. * _Have high stability and accuracy_
They use a 3 digit notation to indicate the dielectric used in them according to EIA RS-198 standard
C0G
| | |
| | |– Tolerance
| |—- Multiplier
|—— Coeffcient
Look at the below table, (Source : Wikipedia)
Class 2 capacitors are specifications mentioned above are for operation within fixed temperature range of +25 degrees centigrade to +85 degrees centigrade.
* * *
Class 2 Capacitors :
Class 2 capacitors have following characteristics
* _Non-Linear temperature coefficient :_ Their capacitance varies non linearly with temperature * _High Voltage dependency :_ Their capacitance highly depends on the applied voltage * _Suffer Aging :_ They suffer significant aging process due to ferro electric materials used in manufacturing * _High electrical losses :_ Have significantly high electrical losses compared to Class 1 capacitors * _High Permittvity :_ Due to high Permittivity they have high volumetric efficiency * _High Capacitance values :_ Due to high Permittivity large capacitance values can be achieved in small device casings like 0201, 0402, 0603 * _Used in smoothing applications :_ Due to the above properties they are used in applications like bypassing, coupling, decoupling. * _Have low stability and accuracy_
They use a 3 digit notation to indicate the dielectric used in them according to EIA RS-198 standard
X7R
| | |
| | |– Tolerance
| |—- Upper limit
|—— Lower limit
Refer the table below, (Source : Wikipedia)
So according to the above table,
When manufacturer says that this is a X7R capacitor, it means that the capacitor can operate from -55 degrees centigrade to +125degrees centigrade temperature and the capacitance of the capacitor will not vary more or less than 10% from its nominal value specified.
Similarly, When manufacturer says that this is a Y5V capacitor, it means that the capacitor can operate from -30 degrees centigrade to +85 degrees centigrade temperature and the capacitance of the capacitor will not increase more than 22% and not decrease below 82% from its nominal value.
Most commonly used capacitor dielectrics are X7R,X8R,X5R,Y5V,Z5U,X7S.
* * *
Although Class 1 capacitors have more advantages than Class 2 capacitors, I encounter more X7R and X5R capacitors on day to day basis than C0G capacitors.
