How to Design for Power Integrity: Power Supply NISM

This short video demonstrates how to use the Sandler Non-Invasive Stability Margin (NISM) measurement algorithm on impedance in the frequency domain to determine control loop stability. This method also provides a way of quantifying the maximum stable case of flat impedance. Regulated power delivery requires a control loop, and if not designed properly, a control loop can easily go unstable and oscillate. Critical power delivery systems for automotive and space applications all have requirements for testing the stability of all power delivery control loops; however, traditional methods are not always possible. Traditional methods, like Bode plots, require access to the control loop for open and closed loop measurements. The new NISM method only requires an external output impedance measurement of the regulated power delivery at the feedback point. 00:00 Introduction 02:55 How to use impedance to calculate voltage regulator stability margin 05:15 How to run the Sandler NISM algorithm in Keysight’s PathWave Advanced Design System (ADS) 06:50 Using regulator ON/OFF states to find the active inductance peak 07:40 How the Sandler NISM stability algorithm also works for input filtering 09:08 Summary Download the project files referred to in this video: Apply for a free trial of ADS: For more information about Picotest: Watch more in this video series: