Overshoot concerns for fixed voltage rails with high layout resistance (Rpath) in advanced SoCs

New features and Intellectual Property (IP) are constantly added into Advanced SoCs. These features result in the increase of max current (ICCmax) demands of the platform, primarily impacting voltage regulators (VR) requirements. Previously only compute power rails consumed high current, but now even the peripheral rails within the same SoC can consume 40A or more. Compute rails are typically able to change their voltages (VID) along with circuitry that can operate at wide voltage ranges. Peripheral rails do not have this feature and will only work with fixed voltages and tolerances. To meet minimum voltage (Vmin) requirements, remote sensing is often used where the sense is placed at the load. This paper explains why this has negative consequences and how it is related to the layout path resistance (Rpath) and the voltage difference between VR output and sense. Voltage regulators can compensate for droop but are mostly bystanders for overshoot, relying only on platform component parameters such as inductance, resistance, and capacitance to mitigate. Calculations and simulation results are shown to demonstrate the behavior. It concludes with the solution space involving layout and VR features to mitigate it as well as how this can be done in early stage SoC development period to avoid future issues.