EIA Class 2 dielectric

The EIA Class 2 dielectric materials are ceramic dielectric materials used in ceramic capacitors.

The EIA Class 2 dielectrics in general are usually based on formulas with high content of barium titanate (BT), possibly mixed with other dielectric electroceramics. Due to its piezoelectric properties, they are subject to microphonics. Other oxides added can be the same as used for Class 1 ceramics.

Contents

Comparison to Class 1 dielectrics

In comparison with the EIA Class 1 dielectrics they tend to have severe temperature drift, high dependence of capacitance on applied voltage, high voltage coefficient of dissipation factor, high frequency coefficient of dissipation, and problems with aging due to gradual change of crystal structure. Aging causes gradual exponential loss of capacitance and decrease of dissipation factor.

Marking code

The EIA three-character code is derived from the minimum and maximum temperature limit, and the amount of capacitance change permitted within that range.

Minimum
temperature
X -55 °C
Y -30 °C
Z +10 °C
Maximum
temperature
4 +65 °C
5 +85 °C
6 +105 °C
7 +125 °C
8 +150 °C
9 +200 °C
Capacitance
change permitted
A ±1.0%
B ±1.5%
C ±2.2%
D ±3.3%
E ±4.7%
F ±7.5%
L +15% / -40%
P ±10%
R ±15%
S ±22%
T +22% / -33%
U +22% / -56%
V +22% / -82%[1]

Common types

Although this code can describe a huge number of possible dielectrics, only a few are commonly manufactured.

X5R performs better than other dielectrics, such as Y5V, and permits the construction of physically smaller capacitors than other dielectrics, such as NP0 and X7R. Typically its temperature variation of capacitance is +/-15% over a range of -55 to +85 degrees Celsius. The temperature variation is, however, non-linear.

X7R is designed for capacitors with capacity ranging typically between 3.3 nF to 330 nF (SMT: 100 pF to 10 µF). Good for non-critical coupling, filtering, transient voltage suppression, and timing applications. Has high dielectric constant. It is an EIA Class 2 dielectric. Its variation over a temperature range of −55 to +125 °C is ±15%.

Y5P and Y5V are other such class 2 ceramics, with temperature range of −30 to +85 °C and wide capacitance change with temperature of ±10% or +22/-82%.[1] Usually used for capacitances between 150 pF and 2 nF (SMT: 10 nF to 10 µF). Y5P is equivalent to the IEC code 2B4.

Z5U is commonly found from 2.2 nF to 2.2 µF, 20%. Good for bypass, coupling applications. Low price and small size, poor temperature stability. This is equivalent to the IEC code 2E6.

References

  1. ^ a b AVX. "Y5V Dielectric" (pdf). siliconexpert.com. http://download.siliconexpert.com/pdfs/Caps/AVX/Cy5v.pdf. Retrieved 2011 October 31. 

See also