Jonathan Fasig, Principal Engineer, Mayo Clinic
Barry Gilbert, Ph.D., Staff Scientist and Director, Mayo Clinic
Erik Daniel, Ph.D.,, Staff Scientist and Deputy Director, Mayo Clinic

As ASIC supply voltages approach one volt, the source-impedance goals for power distribution networks are driven ever lower as well. One approach to achieving these goals is to add decoupling capacitors of various values until the desired impedance profile is obtained. An unintended consequence of this approach can be reduced power supply stability and even oscillation. In this paper, we present a case study of a system design that encountered these problems and describe how these problems were resolved. Time-domain and frequency-domain analysis techniques are discussed, and measured data is presented.