The isolation island and the displacement of decoupling capacitors for power integrity issues

This paper presents a method for power integrity (PI) issue by using the isolation island and decoupling capacitors (de-caps). Deferent form the papers discussed before, the location of voltage regulator module (VRM) is taken into account. Without the de-caps, the fundamental resonant frequency is due to the two-dimensional cavity formed by power plan ground plane and VRM which can deteriorate the whole system. It can be shown that at the lower frequency, delta-I noise can be suppressed by VRM, but at the higher frequency, de-caps should be added to maintain the PI. Isolation island is used to help reducing the number of de-caps. The effects of different stick-ups are also discussed in this paper.