The application note describes how to measure the control loop stability of switch-mode power supplies to get the best performance and confidence of the design. It will explain the main measurement concept and will guide the user during the measurements and mention the main topics in a practical manner. Wherever possible, a hint is given where the user should pay attention to it to avoid weak measurements. The Rohde and Schwarz buck converter reference board was designed in collaboration with Texas Instruments and is used to illustrate the closed loop measurement in a practical manner.