capacitor derating

I am trying to study the effect of temperature on a set of capacitor (the parameter being voltage). In other words , I am looking at how the voltage rating of a capacitor is aeffected with variations in temperature. For eg - consider the derating curve of a capacitor shown in the image. As can be seen, as the temperature increases the voltage rating dips.

I assumed that all capacitor datasheets must have sucha document. I am now refering the datasheet - http://www.avx.com/docs/Catalogs/cx7r.pdf They have not specified any info whatsoever. Can anyone guide me on how to fuind this info please ?

• Electrolytic (aluminum, tantalum) and non-electrolytic (ceramic, plastic film) capacitors are very different. The latter group does not generally have a working voltage dependence on temperature. Sep 11, 2015 at 13:57
• Also, capacitors have a suffix of X7R and X5R asnd so on and so forth. What I understand is that the "R" signifies or denotes the change or deviation from the actual capacitance by +-15%. But is thaat not the tolerance then ? Sep 11, 2015 at 14:24
• I don't understand your question. The datasheet shows how two important parameters, capacitance and leakage, depend on temperature. The X7R ceramic has the nice feature that the temperature coefficient of capacitance is near zero for "room temperature" (0 - 40 C) applications. The "R" does not indicate tolerance; that's indicated by a "J", "K" or "M" following the capacitance value in the part number. Sep 11, 2015 at 14:35
• OK, there are two different tolerances we're talking about here. The "J", "K" or "M" indicates the initial manufacturing tolerance under nominal conditions. The "R" indicates the maximum deviation from the initial value over the operating temperature range. Perhaps you should edit your question to describe your actual application and why temperature is so important to you -- then we could offer more specific advice. As it stands, this is a very broad question. Sep 11, 2015 at 15:37
• maximintegrated.com/en/app-notes/index.mvp/id/5527, This app note seems revelavant to the question, it seems to imply that with class II ceramic capacitors, you do not derate the voltage that can be applied, instead you derate the capacitance value as a function of the applied voltage in addition to the effects of temperature Sep 11, 2015 at 15:44