Capacitor Voltage rating - using higher voltage

[ballimo]

Capacitor Voltage rating

Hello All,

Usually in a design there is many chip with different voltage supply (1V,3.3V,5V and 12V as main supply per example), if we need to use a ceramic capacitor value of 10 uF per example for DC coupling. can we use a 10 uF capacitor with a voltage range of 16 V for the 1V voltage supply? what is the risk? I am asking this question, because I want to use one manufacturer part number for all the supply voltages.

Thanks,
Ballimo

 

[Tahmid]

Capacitor Voltage rating

Hi,
I don't think there's any risk as, for capacitor, you should use something that's rated at atleast 2x for safety, less may work. For 1v, you can use any capacitor rated at 3v and above (for safety). For 12v, it's better you use 25v caps.
Hope this helps.
Tahmid.

 

[JoannesPaulus]

Capacitor Voltage rating

No risk, higher cost.

 

[karesz]

Capacitor Voltage rating

Hi,
Their is no risk, but an effect is knowed by ceramics capacitors if working Voltage is (much)lower as nominal voltage!
Their capacitance loss is depend of ceramics as X7R(the best) or X5R,Y5VUu(is maybe the most worse), but a little bit has a same type of dielectrics from other producer not the same data..., and the voltage difference between nominal and working values_it can be up to 30-50% less capacitance has as nominal value + the specified +/.20%...
Also in worst case you can have real only a portion of your desired/nominal nFs!!:-(
It is a muss to calculate with them for a professional developer!
BAD IS: not all producer has the right characteristics of these capacitance-value depending of working voltage in hes catalog!
K.

 

[ballimo]

Re: Capacitor Voltage rating

Hi Karesz,

do you have a datasheet(or catalog) for a capacitor, where we have the capacitance value function of the working voltage?

Thanks,
Ballimo

 

[karesz]

Capacitor Voltage rating

Hallo ballimo,
Because I have had these problem so good 10 years ago, sorry _ I would say; search pls i.e. by AVX,ITW..., or at all better producer...
K.

 

[IanP]

Re: Capacitor Voltage rating

Are you sure you are talking about ceramic capacitors?
With all due respect to what has been said here so far, it is rather difficult and very unlikely to come across 10uF CERAMIC decoupling capacitor ..
Most of them are electrolytic or tantalum ..

As the capacitance of a ceramic cap very little depends on the working voltage .. What are you talking about?

And lastly, if you need a decupling capacitor working with 1V supply choose any cap available on the market ..
They are all rated well above that value ..

Rgds,
IanP

 

[karesz]

Capacitor Voltage rating

Aha,
these means, all what I wrote is idiotic?:-( oh-oh-oh...
I have yet no more time to search for detailed characteristics, found some, but not what I mean...

Maybe can find it somebody pls?
Sure spoke I over ceramics, than I know why I have i.e. 22uF/1206/X7R in my as possible good product
K.