Author Topic: High value ceramic caps reliability  (Read 1626 times)

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Offline ivan747

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High value ceramic caps reliability
« on: October 08, 2011, 06:19:21 pm »
Hi, I am converting a board I did to a lower profile design. That meant changing a 47µF electrolythic with a ceramic one. Is the board flex going to affect the capacitance too much, at this high values. Mind you, it's a 1.6mm thick prototyping board with some connector on it. (OK, I admit it. It's an Arduino compatible).

Thanks again!
 

Offline Zero999

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Re: High value ceramic caps reliability
« Reply #1 on: October 09, 2011, 02:24:35 pm »
Is the capacitance value critical?

If so you've chosen the wrong type of capacitor be it electrolytic or ceramic. Electrolytic have a wide tolerance and some (I'm sure others here will remind me of the dielectrics I'm talking about here) ceramics are piezoelectric and have a nasty voltage/capacitance coefficient.
 

alm

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Re: High value ceramic caps reliability
« Reply #2 on: October 09, 2011, 02:49:12 pm »
I believe the nasty dielectrics are the class III ones like Z5U and Y5V, which also happen to make it possible to get large capacitance values in small packages. Tantalum may be another option, they used to be the more stable alternative for aluminum electrolytics before high-value ceramics came along.
 


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