The question is basically: why use capacitor in this particular DC circuit? Generally, as I read in the thread below, using a capacitor in DC circuit may have different reasons and purposes. Given my lack on knowledge in the topic I do not know what is the reason for using it here.
Here I am talking about the 10nF capacitor right after USB GND. Basically it connects USB GND with USB VCC. Given that USB is DC isn't it just a break in the circuit? Or, if we assume that some significant current can actually flow there, wouldn't we be causing s/c?
I understand that that this partial circuit shown at the bottom of the picture is something we could use instead of this 10nF and ferrite bead setup. So my thinking is that all these capacitors are here only for some EMI filtration. Is that correct? If yes, why is it so important to filter it here on the power terminals rather than maybe data terminals? Will it cause problems if we skip it completely? And why we are doing nothing with the data terminals? Thanks.
The picture comes from http://www.ftdichip.com/Support/Documents/DataSheets/ICs/DS_FT232R.pdf