Should capacitors be mounted in parallel?

The goal of mounting capacitors in parallel is to re-duce ESL and ESR, and thereby be more effective in filtering out high-frequency noise. However, it is not the only solution. An obvious alternative is to use a single low-ESL capacitor instead of the pair of parallel capacitors.

Should decoupling capacitors be placed in parallel?

Contrariwise, [Danker 2011] recommends against placing decoupling capacitors in parallel (regard-less of whether these capacitors are different or identical). Finally, [Ott 2009] recommends putting two capacitors in parallel, but in contrast to Archambeault he asserts that both should be identical,1 citing the risk of antiresonance.

Is a capacitor a resonant filter?

The traceto the capacitor likewise contributes some inductance and resistance. A real-world capacitor should therefore be modelled as an RLC filter: it has a resonant frequency, above which the effectiveness of the capacitance is can-celled out by the parasitic inductance.

Why does a capacitor have a harmonic resonance?

Moreover, the system parameters are dynamically changed; therefore, harmonic resonance might occur even if it had been studied before the capacitor installation. Resonance current flowing through the capacitor, as well as through the power source can be damped by using an antiresonance hybrid capacitor system.

What are the chances of anti resonance b/w different capacitor values?

It depends on the whole system (containing power planes,decaps etc). When multiple numbers of same value capacitors are used there are high chances of Anti resonance with power planes, same way when multiple numbers of different values capacitors are used there are high chances of anti resonance b/w different capacitor values.

What type of capacitor should I use for parallering ICS?

General rule of thumb with parallering caps is that you have a "large" tank capacitor (can be electrolytic or "large" MLCC) and then a smaller capacitor to catch high frequencies which can be tuned to fundamental switching frequency of the IC (think sampling frequency, PHY signaling frequency..).