Far-End Crosstalk Mitigation Using Homogeneous Dielectric Substrate in DDR5

Far-end crosstalk (FEXT) can be a problem in the design of printed circuit boards (PCB) for the incoming fifth generation double data rate (DDR5). In this paper, a FEXT mitigation method is proposed. This method adds an additional layer of homogeneous dielectric substrate with or without metal to make the transmission line more homogeneous. Therefore, the capacitive crosstalk can cancel out more inductive crosstalk at the far end. In our research, transmission lines with or without tabbed routing are analyzed and simulated. Finally, the frequency-domain and time-domain simulated results show that, in straight line areas, the dielectric substrate without metal achieves higher crosstalk reduction, while in tabbed routing areas, substrate with metal achieves better performances.