I’ve had to make the hard decision as to what type of capacitors to use in a power supply I’ve been designing. I need a 5.0v, 3.3v, 1.9v and 1.2v rails powered by a 12v adaptor. The 5.0v and 3.3v rails use a DC/DC switching regulator while the 1.9v and 1.2v use a LDO regulator feed from the 3.3v rail. Both require bypass/filtering capacitors and I’ve traditionally used 10uF 16V 20% Tantalums — for some reason the “Case B” end up being cheaper than the 2010 sized equivalent of the X7R MLCC (ceramic).
I understand the pro’s and con’s of each:
Ceramic benefits over Tantalum
- smaller sizes
- don’t explode
Tantalum benefits over Ceramic
- cheaper (at least for the sizes I’m finding)
- look nicer on boards
- fixed capacitance, does not changes with voltage
I’ve read lots of white papers and there seems to be no clear answer to which capacitor is better. I’d love to here what you think. Please post your experiences/preferences in the comments.