Ceramic Capacitor Dielectric Types: X7R, Y5V, C0G, etc

Ceramic capacitors can use a wide variety of types of dielectric, each type offering different performance levels and is intended for use in different applications. Common types include C0G, NP0, X7R, Y5V, Z5U and many more.

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Ceramic capacitor can utilise a whole host of different dielectrics. These different dielectrics give the capacitors very different properties, so apart from choosing that a ceramic capacitor is to be used, a second decision about the specific type of dielectric may also be needed.

Mention is often made of common ceramic capacitor dielectrics including C0G, NP0, X7R, Y5V, Z5U and many more will be seen specified in distributors list. But knowing which type is best requires a little further investigation.

Ceramic capacitor indicating the dielectric type: X7R
Ceramic capacitor with markings indicating dielectric type (X7R)

Ceramic capacitor dielectric classes

In order to simplify the selection of capacitors with the required dielectric, some industry organisations have defined a number of ceramic dielectric application classes.

These application classes split the different dielectrics available for ceramic capacitors into different classes according to the anticipated application.

Ceramic Capacitor Dielectric Application Classes
Class Description Common types
Class 1 These ceramic capacitors offer a high level of stability and exhibit low loss levels and they are ideal for use in resonant circuits. NP0, P100, N33, N75, etc.
Class 2 Class 2 ceramic capacitors offer high volumetric efficiency, i.e. large capacitance for a given volume for smoothing, by-pass, coupling and decoupling applications. X7R, X5R, Y5V, Z5U, etc.
Class 3 Class 3 ceramic capacitors offer higher volumetric efficiency than the class 2 ceramic capacitors, but their temperature stability is not nearly so good. A typical performance for the change of capacitance with temperature is −22% to +56% over a range of 10°C to 55°C. Only available as leaded components. No longer standardised.

These ceramic capacitor classes are standardised by international bodies including the IEC, International Electrotechnical Commission and the EIA, Electronic Industries Alliance.

Class 1 ceramic capacitor dielectric

Ceramic capacitors that use class 1 dielectrics offer the highest performance in terms of stability and loss. They can provide accurate high tolerance capacitors with stable voltage and temperature coefficients. They also offer low losses and are therefore suitable for use in oscillators, filters and the like.

Class 1 ceramic dielectrics are normally based on finely ground materials like Titanium dioxide (TiO2), with additives of Zinc, Zirconium, Niobium, Magnesium, Tantalum, Cobalt and Strontium, although many modern C0G (NP0) formulations contain neodymium, samarium and other rare earth oxides.

Class 1 capacitor codes:

To define the performance of a ceramic capacitor dielectric a three character code is used which is specific to ceramic capacitor class 1 dielectrics.

  • The first character is a letter which gives the significant figure of the change in capacitance over temperature in ppm/°C
  • The second character is numeric and gives the multiplier
  • The third character is a letter and gives the maximum error in ppm/C

The table below details what each of the EIA codes means.

First character Second character Third character
Letter Sig Figs* Digit Multiplier 10x Letter Tolerance
C 0.0 0 -1 G +/-30
B 0.3 1 -10 H +/-60
L 0.8 2 -100 J +/-120
A 0.9 3 -1000 K +/-250
M 1.0 4 +1 L +/-500
P 1.5 6 +10 M +/-1000
R 2.2 7 +100 N +/-2500
S 3.3 8 +1000    
T 4.7        
V 5.6        
U 7.5        

As an example, one common type of class 1 capacitor is a C0G and this will have 0 drift, with an error of ±30ppm/°C.

C0G (NP0) is the most popular formulation of the EIA Class 1 ceramic materials.

C0G (NP0) ceramics offer one of the most stable capacitor dielectrics available. Capacitance change with temperature is 0 ±30ppm/°C which is less than ±0.3% ΔC from -55°C to +125°C. Capacitance drift or hysteresis for C0G (NP0) ceramics is negligible at less than ±±0.05% versus up to ±2% for films.

The C0G (NP0) ceramic dielectric usually has a “Q” in excess of 1000 and shows little capacitance or “Q” changes with frequency. In addition to this, the dielectric absorption is typically less than 0.6% which is similar to mica which is renowned for having a very low absorption.

SMD ceramic capacitor selection
SMD ceramic capacitor selection

Class 2 ceramic capacitor dielectric

Ceramic capacitor class 2 dielectrics have a much higher level of permittivity than their class 1 counterparts. This gives them a much higher capacitance level for a given volume, i.e. better volumetric capacitance efficiency. However this is at the expense of accuracy and stability. In addition to this they exhibit a non-linear temperature coefficient and a capacitance that is dependent to a small degree on the applied voltage.

As a result of these characteristics, they are ideal for decoupling and coupling applications where the exact value of capacitance is not critical, but where space may be an issue.

Class 2 capacitor codes

A three code is used to define the performance of ceramic capacitor dielectric.

  • The first character is a letter. This gives the low-end operating temperature.
  • The second is numeric and indicates the high-end operating temperature.
  • The third character is a letter which indicates the capacitance change over the temperature range.

The table below details what each of the EIA codes means.

First character Second character Third character
Letter Low Temp Digit High Temp Letter Change
X -55C (-67F) 2 +45C (+113F) D +/-3.3%
Y -30C (-22F) 4 +65 (+149F) E +/-4.7%
Z +10C (+50F) 5 +85 (+185F) F +/-7.5%
    6 +105 (+221F) P +/-10%
    7 +125 (+257F) R +/-15%
        S +/-22%
        T +22% / -33%
        U +22% / -56%
        V +22% / -82%

Popular class 2 ceramic dielectrics include X7R which as a temperature range of −55 to+125°C, with a ΔC/C0 of ±15%, Y5V which as a temperature range of −30 to+85°C with a ΔC/C0 of +22/−82%, and Z5U which has a temperature range of +10 to +85°C and a ΔC/C0 = +22/−56%.

Class 3 ceramic capacitor dielectric

Class 3 ceramic capacitor dielectrics provide an exceedingly high level of permittivity with figures for the permittivity rising to 50 000 times those of some class 2 ceramics.

On the downside, these capacitor dielectrics are much inferior in terms of accuracy and stability as well as ageing over time, voltage dependent capacitance, a non-linear temperature characteristic and high losses.

Another drawback of these capacitors is that tit is not possible to manufacture them in a multilayer format, ruling out surface mount versions.

These capacitors were overtaken by other technologies with the result that they are no longer standardised by the IEC or EIA.

Class 4 ceramic capacitor dielectric

These were what were termed barrier layer capacitors. Although they used high permittivity dielectrics, they have been superseded by other types and have not been standardised for some time.

There is a wide variety of dielectrics that can be used for ceramic capacitors. Their performance is carefully tailored to ensure they meet the required performance levels. When choosing a ceramic capacitor for a particular application, referring to the tables above can provide the required insight.

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