Electrolytic/tantalum or ceramic capacitance?

Other Hardware General Electronics
1

Hi guys,

I seek you advice here. For a new board I have to make a decision to use solely ceramic capacitance or for certain ones (1uF and 10uF) take a electrolytic/tantalum cap?

The electrolytic/tantalum caps I would only consider for the supply pins of the main IC's (including the Atmega), the question is if it's really necessary. Voltage range is 5V (with line disturbances maybe up to 6V), currents are in the 200mA range max. I know from the hardware manufacturer, that 1uF and 10uF caps are available as ceramic ones, which are much cheaper and smaller than electrolytic/tantalum ones, and the latter tend to explode/short circuit if reverse polarized.

So at the moment I tend to think that I can get along well with ceramic caps only. But most of the Arduino boards have electrolytic/tantalum caps, which makes me unsure. Is there a special reason for that? What are the pros/cons of electrolytic/tantalum vs. ceramic caps?

I would be very grateful for a good, short overview...

Thanks in advance guys and Cheers: Protonerd

2

It is only comparatively recently you have been able to get ceramic capacitors that large. They are quite lossy and the capacitance changes with the applied voltage. However this is not a problem for supply decoupling so you can use them but I wouldn't use them for anything else.

3

Interesting comparison here
It would seem that the capacitance will drop by about 10% at 5V dc but that the losses (esr) are lower than for tantalum and electrolytics. Of course that document is produced by a company trying to sell ceramics :confused:

Russell.

4

Thanks a lot guys for the promt answers! For the first builds I will order ceramic caps for each and every one of them on the board, but will design a footprint so that the smaller electrolytics can still fit if needed.