Difference between X7R, X5R, X8R, Z5U,Y5V, X7S, C0G Capacitor dielectrics

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 +125 degrees centigrade temperature and the capacitance of the capacitor will not vary more or less than 15% 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. 

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