A CMOS Low Dropout Regulator with Extended Stable Region for the Effective Series Resistance of the Output Capacitor

摘要

In this paper, a new compensation scheme and a corresponding pass element structure for a CMOS low-dropout regulator (LDO) are presented. The proposed approach effectively alleviates the strict stability constraint on the ESR of the output capacitor. Stability of a CMOS LDO with the conventional compensation requires the effective series resistance (ESR) of the output capacitor in a tunnel-like region. With the proposed design approach, an LDO can be stable using an output capacitor without ESR. A 2.5 V/150 mA LDO has been implemented using a 0.5-μm 1P2M CMOS process. The experimental results illustrate that the proposed LDO is stable with an output capacitor of 0.33 μF and no ESR.