What is really better, to use tantalum capacitors or a bank of ceramic capacitors for filtering in the input and output of the regulator considering performance?
A bank of MLCCs (multilayer ceramic capacitors) will provide a much lower ESR than Tantalum capacitors and consequently a lower output voltage ripple when used with a switching regulator.
Tantalums typically are larger, have a higher profile, more costly, and are less reliable than MLCCs especially when operated at high temperature. Therefore MLCCs are preferred for switching power supplies.
ADI recommends only using X5R or X7R dielectric MLCCs with their switching regulators.
As always, there’s some good information to be found on the web, here’s one link for a MLCC vs. Tantalum comparison: http://www.venkel.com/presentation/tant_vs_mlcc.htm
I'm considering a JB dielectric MLCC as an alternative to a tantalum to bypass the output of an ADuM3223. It's cheaper than the equivalent tantalum, and far higher capacitance than an X5R or X7R. Because I'm using it as a bypass cap, I don't need to pay more for tantalum's temperature stability.
Two things can be consider for using Tantalum capacitors instead of ceramic capacitors:
1) Tantalum capacitors can sometimes be found with a very high capacitance (more than 470 uF) in a single reasonably sized component (EG 7.3x4.3 mm). This could possibly reduce assembly cost or allow an easier layout.
2) Tantalum capacitor rarely (if ever) generate acoustic noise. Ceramic capacitors and some inductors often generate an easily audible acoustic high pitched noise if used in switched designs. This acoustic noise is often independent of the switching frequency. This presents a problem for many high end consumer products.
All in all I would say that ceramic capacitors are still the way to go for all traditional designs.
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