Analysis and suppression of SSN noise coupling between power/ground plane cavities through cutouts in multilayer packages and PCBs

We introduce a model of simultaneous switching noise (SSN) coupling between the power/ground plane cavities through cutouts in high-speed and high-density multilayer packages and printed circuit boards (PCBs). Usually, the cutouts are used in multilayer plane structures to isolate the SSN of noisy digital circuits from sensitive analog circuits or to provide multiple voltage levels. The noise-coupling model is expressed in terms of the transfer impedance. The. proposed modeling and analysis results are compared with measured data up to 10 GHz to demonstrate the validity of the model. It is demonstrated that the cutout is the major gate for SSN coupling between the plane cavities, and that substantial SSN coupling occurs between the plane cavities through the cutout at the resonant frequencies of the plane cavities. We also analyze and discuss the coupling mechanism and characteristics of the noise coupling, from which we evaluate a method of suppression of the SSN coupling. Proper positioning of the cutout and the devices at each plane cavity achieves significant noise suppression at certain resonant frequencies. The suggested suppression method of the SSN coupling was successfully proved by frequency domain measurement and time domain analysis.