Relation between internal terminal voltage and immunity behavior of LDO regulator circuits

Because predicting undesired behaviors in IC (Integrated Circuit) due to conducted electromagnetic disturbances is necessary for front-loading the design process, immunity models are becoming more important to predict a malfunction at the design stage of electronic products. In this paper, the failure to function mechanism in a LDO (Low Dropout) voltage regulator is investigated from the aspect of the internal terminal in a circuit. Simulations confirm a relation between the internal reference voltage and the DC shift error at certain frequencies. Thus, monitoring the voltage or current at an internal terminal between functional blocks gives useful information about an IC model to predict immunity.