[Gta04-owner] GTA04 capacitor selection

Glenn glenn.mh.dk at gmail.com
Mon Jan 24 05:50:31 CET 2011


Another suggestion regarding capacitor selection.

As far as I know, aluminium capacitor have relatively short 
lifetimes, are more error prone - they dry out over time, and in the 
same proces get bigger ESR. I have encountered capacitors in linear 
power supplies, that failed after 1,5 years use.

-

Therefore it is suggested that ceramic capacitors are selected 
instead - bonus - they are bipolar and they are smaller!

There might be one problem with low-ESR - I assume - possible HF 
ringing, but that can be minimized by distributing the big central 
capacitors into many smaller at the ICs, and bypassing with a 
1/10...1/100 capacitance of the big capacitor.

Cheapest - most are even low-ESR:

68eu/100
CAP CER 100UF 6.3V Y5V 1210
http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=587-1397-1-ND

118eu/100
Low ESR
CAP CER 100UF 6.3V X5R 20% 1206
http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=445-6008-1-ND

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5,6eu/100
Low ESR
CAP CER 10UF 10V Y5V 0805
http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=445-1371-1-ND

11eu/100
Low ESR
CAP CER 10UF 16V Y5V 1206
http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=445-1391-1-ND

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22eu/100
Low ESR
CAP 22UF 10V CERAMIC F 1206
http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=PCC2236CT-ND

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Other information

ESR:
http://en.wikipedia.org/wiki/Equivalent_series_resistance

More expensive - but good in high power SMPS:
Aug 1, 2007, Stacked-Ceramic Caps Brave High Temperatures:
http://powerelectronics.com/passive_components_packaging_interconnects/capacitors/708PET24.pdf
http://powerelectronics.com/passive_components_packaging_interconnects/capacitors/stacked-ceramic-caps-smps-0807/
X9U, X8R

regards,

Glenn


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