Target Impedance and Rogue Waves
The target impedance concept has been used by the industry for a number of years. It is the basis of a simple and robust design process, but it assumes a smooth flat impedance profile. Looking out from the silicon, the impedance profile is never flat, which results in higher noise. Excitation patterns that can create the worst-case or almost-worst-case time-domain response of a power distribution network has gained a lot of interest in recent years. The peak value of the step response, the response to a repetitive excitation at a resonance peak as well as the absolute worst-case time-domain response are potentially producing results much worse than target impedance alone would imply. The panel will discuss how these are related, how the target impedance concept can be applied under such circumstances as well as providing tips for recognizing and avoiding rogue waves. Rogue wave measurements will also be shown.
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