[sdiy] Paralleling MLCCs

[Paul Schreiber]

This is commonly done for the outputs of switching power supplies (to get ripple current specs which in turn is based on lowering ESR). Om my Euro modules that use a switcher, I parallel caps on both input and output side. I have seen 10 caps in parallel before for large (say 5A) outputs.

The other place to parallel is when the SFR (self-resonance frequency) comes into play (in the MHz-GHz range). In cell phones, this is used all over the place, where you pick a part not for the value at all, but the SRF. An example is applying SFR caps to headphone jacks to keep the GPS radio frequencies from interfering (which I personally spent 5 weeks screwing with, it's a CE specification).

Paul S.