There are half-a-dozen ceramic dielectrics in regular use today: the ultra stable Class 1 types P90 (porcelain), NPO (COG) and U2J (N2200), and the stable Class II types X7R, X5R and Y5V.
With increasing use of electronic modules in under-the-hood applications in the automotive industry, X8* type ceramic dielectrics are also becoming more and more popular.
X8G, X8L and X8R are all high temperature ceramic dielectrics for use in demanding applications up to +150°C, and all have a lower operating temperature limit of -55°C. This is what the “X” and the “8” signify. The third character represents the capacitance change over this temperature range. The table below shows this capacitance change.
|Ceramic Type||Rated Temperature Range||Maximum Capacitance Change Over Temperature Range|
|X8G||-55°C - +150°C||0±30ppm/°C|
|X8L||-55°C - +150°C||±15%|
|X8R||-55°C - +150°C||+15/-40%|
This means that X8L and X8R types are stable Class II dielectrics, while the rarer X8G type is an ultra stable Class I dielectric.
The table below lists data sheets for all XRG, X8L and X8R capacitors in production today.
Major brands such as AVX, KEMET, Knowles, Murata, TDK and Vishay all produce X8L/X8R dielectrics, but only Knowles and Murata have X8G types.