Maker Pro
Maker Pro

Decoupling capacitors

CommanderLake

Oct 2, 2012
227
Joined
Oct 2, 2012
Messages
227
Can I use a 10µF ceramic instead of a 10µF electrolytic and 0.1µF film with an LM3886 to save space?
 

davenn

Moderator
Sep 5, 2009
14,254
Joined
Sep 5, 2009
Messages
14,254
you need the 0.1uF
it isn't the same as a 10uF ;)
not sure what you are referring to as a 10uF ceramic ? I have never seen a 10uF ceramic

Dave
 

KrisBlueNZ

Sadly passed away in 2015
Nov 28, 2011
8,393
Joined
Nov 28, 2011
Messages
8,393
I would always use what the data sheet recommends, unless I thought I knew more than the authors of the data sheet!
 

CommanderLake

Oct 2, 2012
227
Joined
Oct 2, 2012
Messages
227
I've just tested the volt drop of various electrolytics, film and ceramic capacitors with my USB oscilloscope, a 3.8v battery source and a 10 ohm load and the results are as follows:

With no capacitor there are wild peaks and dips when the load is applied.

Aluminium electrolytics remove noise and wild peaks and drops when the load is applied but dont slow the immediate volt drop.

Film and ceramic eliminate the sudden volt drop and smooth it to a gentle slope, smaller values dip slightly before stabilizing.

A larger aluminium electrolytic along side a smaller film capacitor doesnt do much at all, if anything its more stable without the electrolytic.
 
Last edited:

Arouse1973

Adam
Dec 18, 2013
5,178
Joined
Dec 18, 2013
Messages
5,178
you need the 0.1uF
it isn't the same as a 10uF ;)
not sure what you are referring to as a 10uF ceramic ? I have never seen a 10uF ceramic

Dave

I use 10uF ceramics as standard PDS support on most of my designs now. I even use some 100uF ceramics for certain applications. For the 100uF I limit the working voltage to about 6.3V, otherwise they get very expensive.

Adam
 
Top