Techniques for Suppressing △I Noise by using Decoupling Capacitors

Suppressing △I noise in digital circuits by using decoupling capacitors on PCBs is faced with some challenges.How the parasitic parameters of a decoupling capacitor affects its high frequency performance is analyzed,how to select decoupling capacitors outlined,and the use of the multiple decoupling capacitors for suppressing △I noise discussed in this paper.The results illustrate that using multiple decoupling capacitors and selecting properly the type,number,capacitance,and self-resonant frequency of the decoupling capacitors are essential to the expected equivalent impedance curve of decoupling capacitors.