Enhancing Ultra-low Impedance Measurement Techniques for High-performance Power Delivery Networks

Voltage regulator impedance characterization is a straightforward concept but the challenges in making high-fidelity measurements are numerous as the impedance becomes progressively smaller. This paper evaluates techniques used for low impedance buck converters requiring large-signal current perturbations to properly characterize the impedance. Additionally, the paper addresses how high-performance time-domain characterization equipment can be utilized to generate frequency-domain impedance plots. A number of parameters that can affect the impedance plots were studied and tuned. Some of the measurement challenges when collecting this data are examined.