Ceramic Caps - Drawbacks to Higher Voltage

[Noggin]

What are the drawbacks to choosing a higher voltage ceramic capacitor vs a lower voltage with all other documented specs being equal? If I'm not mistaken, higher voltage rated caps for electrolytic caps result in a larger physical size as well as higher ESR. Just don't know what differences there are in the ceramic caps. Maybe its just a batch/bin type of rating.

AVX 08055C152KAT2A 50v, X7R, 0805, +/-10%, 55-125 deg C
AVX 08051C152KAT2A 100v, X74, 0805, +/-10%, 55-125 deg C

Hmm... getting up in the >.1uF range, it looks like cost is a difference. A 1.0uF cap from Murata, 10v cap vs. 50v cap, is about $0.07 vs $0.29 (Digi-Key 100 qty pricing). I may have to sort my list and find cheaper lower voltage parts for everything over something like 15 cents. Heck, who cares about the expensive ones. So long as I have a cheap 0.1uF, some cheap pF, and a cheap 1uF I should be good.

 

[dknguyen]

Google around for ceramic capacitor derating. THat should give you your answer.

 

[Ubergeek63]

the combination of high voltage, high value, and small size increases the ESR and leakage. Y5V material is useless unless you actually want your circuit to be both voltage and temperature sensative! Well actually ANY "Y" ceramic.

I use a wonderful 3KV 10pF NPO ceramic capacitor for a CCFL inverter feedback divider. It is about 10mm by 3mm and costs $0.25 each in a reel.

Dan

 

[Noggin]

Aight, thanks. I'm just making a library of parts to use at work. Currently, our library is populated with compnents with ZERO information other than value. No manufacturers, part number, nothing. All BOMs are done by hand. This library will be useful. Just wanted to make sure that I wasn't picking MLCCs that were going to be bad for general purpose use. Almost everything I picked was 50v in an 0805 package with either C0G or X7R dielectric. Don't think I'll have a problem with that for general purpose use.

 

[Ubergeek63]

Ouch. There should be no problem, just avoid the Y series materials and keep the Xs and Cs separated (the Cs are the same as NPOs for practical purposes) so you can use the Cs for critical or high frequency stuff.

If you are worried you can get the curves from the mfgs but it is easy enough to find typical material curves on the web. Ceramic capacitor - Wikipedia, the free encyclopedia has the actual tempco code tables.