Nonlinear Behavior Immunity Modeling of an LDO Voltage Regulator Under Conducted EMI

This paper presents a nonlinear behavior modeling method committed to the immunity of low-dropout (LDO) voltage regulator to conducted electromagnetic interference (EMI). A nonlinear behavior model is proposed to predict the immunity of LDOs, where the nonlinear characteristics of an LDO voltage regulator are described as a cascade of Taylor series and linear filter system. A test printed circuit board (PCB), using the direct power injection (DPI) method, is designed up to 2 GHz to measure the immunity of LDOs. A nonlinear behavior model, lump-parameter models of discrete components on PCB extracted from
S
-parameter measurement, and DPI method are used to predict the immunity of an LDO voltage regulator. The comparison of immunity between simulation and measurement shows that the model has a good fit up to 2 GHz.