To reduce power rail voltage fluctuations that could lead to noise emissions, it is critical to keep the power plane's impedance below a target and minimize impedance peaks over frequency. Previous studies have shown that RC power plane termination can reduce power plane impedance peaks including on an electrically dense production board where decoupling capacitors would not fit near critical memory components. In this study, we use measurements and simulations on a production board to show how RC termination impacts resonance distribution, the resonance Q-value, and voltage domain noise. We show how these translate into signal integrity performance and crosstalk.
RC power plane termination is a simple, low-cost technique using the least valuable PCB real estate at the edge of the power plane. We will show that this technique not only reduces power plane impedance peaks to improve voltage noise but can also improve the signal performance of nearby traces. In this way RC termination should not only be considered a last resort relegated to the EMC specialist but something that can be actively incorporated as a power integrity design strategy and something that should be considered to mitigate the influence of power plane resonances on signal integrity.