[sdiy] Cap heads-up

[Ian Fritz]

ezion --

The ones I was refering to are not SMD.  I don't see anything on the data 
sheeet about derating or hysteresis.  Voltage ratings ar 50V and up, so we 
generally wouldn't get to half of that anyway.

Am I missing something?

Ian



At 01:01 AM 5/6/2011, ezion wrote:
>Hi Ian
>Certainly worth a look, however you might want to get a in depth look
>at the data sheet.
>It has been a few months since I last looked at high value (SMD) ceramics 
>but...
>High value ceramics de-rate with applied voltage, often the
>capacitance goes down rather quickly.
>Think 5 to 20% of the capacitance left @ half the maximum voltage.
>And some models show quite prominent dielectric hysteresis.
>
>For AC coupling these parts are usually fine.
>However for DC storage of energy, read the data sheet and keep in mind
>that the same value COG form another brand or other series might
>behave rather differently.
>
>
>Cheers
>Theo
>
>
>
>On Wed, May 4, 2011 at 7:55 PM, Ian Fritz <ijfritz at comcast.net> wrote:
> > Maybe everyone already knows this, but I don't remember it being mentioned
> > here.  C0G ceramic caps are now available in values up to 0.22uF.  If their
> > leakage is as good as for the lower values, these could be interesting for
> > very low frequency LFOs, S/H circuits, etc.
> >
> > Digi # is 445-4758-ND
> > TDK# is FK22C0G1H224J
> >
> > Ian
> >
> > _______________________________________________
> > Synth-diy mailing list
> > Synth-diy at dropmix.xs4all.nl
> > http://dropmix.xs4all.nl/mailman/listinfo/synth-diy
> >