A linear LDO regulator with modified NMCF frequency compensation independent of off-chip capacitor and ESR

Abstract

This paper presents a novel compensation design for regulators, i.e., modified NMCF (nested Miller compensation with feedforward Gm stage), resulting in a linear LDO (low dropout) regulator whose performance is independent of the off-chip capacitor and its ESR (equivalent series resistor). The proposed compensation method ensures the stability of the feedback loop and the sufficient phase margin of the LDO regulator. Besides, the transient response become faster. The analysis of the stability is derived to solidify the proposed design. The proposed design is implemented using TSMC 0.35 lm 2P4M CMOS process. The results verify the performance and the stability on silicon. The power supply rejection ratio is 25 dB @ [200 Hz, 3 MHz], [50 X, 500 X] provided that the input voltage varies from 4 to 5 V.