Did you take a gander at this?

http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=283-3015-ND

-marc

On Fri, Feb 5, 2010 at 3:37 PM, William "Chops" Westfield <westfw@mac.com>wrote:

>
> On Feb 5, 2010, at 10:48 AM, Isaac Marino Bavaresco wrote:
>
> > Very expensive though (over $25 only the cap).
>
> Um.  You're looking at different caps than I would.
>
> You need to know how much current your device will need, and what the
> minimum voltage it can use.  Isaac's capacitor is particularly
> expensive because he wanted a starting voltage of 6.5V and a current
> capability of 150mA, which moves it out of the realm of most
> "supercaps."  (You can get a .47F supercap with high current
> capability for about $4, but it's only 5.5V.  Or you can get a .1F
> 6.3V double layer cap for about $6, but it's not spec'ed for high
> current. (hmm.  30mohm.  MIGHT work...)  Or 3x 1.5F 2.5V caps (0.5F @
> 7.5V in series) for about $3 each.)
>
> The "usual" setup seems to be to just connect the cap across the
> supply rails of of memory/microprocessor chips that are designed to
> have some level of operation down to voltages significantly lower than
> their normal supply voltage...  Adding more capacitors for higher
> voltage seems to be about the same price as adding a boost converter
> style UPS circuit...
>
> BillW
>
> --
> http://www.piclist.com PIC/SX FAQ & list archive
> View/change your membership options at
> http://mailman.mit.edu/mailman/listinfo/piclist
>
-- 
http://www.piclist.com PIC/SX FAQ & list archive
View/change your membership options at
http://mailman.mit.edu/mailman/listinfo/piclist