The impact of the planes parameters on the noise of a power distribution network

The goal of a power distribution network is to have a flat impedance over the entire frequency range. This goal may or may not be achievable depending on the system requirements. In case the flatness cannot be achieved, the design will exhibit some parallel resonance. The magnitude of the parallel impedance will have to be determined to make sure that the voltage drop does not exceed expectations, so this voltage drop that the current switching generates on printed circuit board power planes is becoming an increasingly important problem in high frequencies designs. Both switching rates and switching current amplitudes are increasing with each new generation of chip design. The conventional techniques that reduce the noise, including the use of multiple decoupling capacitors, are becoming less effective at higher frequencies. Frequency domain solutions are used because can incorporate many subtle effects that are not easily computed in a time-domain solution. These effects include losses in the copper power/ground planes due to skin effects and losses in the laminate used to separate the ground and power planes. Ignoring these effects can result in substantial errors in designing a system with less noise.