slyt187Power ManagementTexas Instruments IncorporatedUnderstanding the stable range of equivalent series resistance of an LDO regulatorBy Bang S. LeeApplication Specialist, Power ManagementThis application note explores the stable range of equivalent series resistance (ESR) values for LDO regulators. An ac model of an LDO regulator is presented to discuss the LDO frequency response. Both stable and unstable ESR ranges are examined.Figure 1. An ac model of a linear regulatorSeries Pass Element G + vgsg p Rds D Zo + R2 ga R1 VREF ……