A Fast Transient Full Class AB LDO Regulator

Abstract

A novel fully integrated Low Dropout Regulator (LDO) using a class AB error amplifier, class AB indirect compensation and a QFG-based dynamic transient enhancement circuit is presented in this paper. The LDO was designed in a 180nm CMOS process with a 2.1-3V input supply and 1. 8V regulated output voltage. Post-layout simulations show a line regulation of 3mVN and a load regulation of 77$\mu$V/mA. For large load transients from 0 to 50mA, the overshoot and undershoot values are less than 330mV and 211mV, with a recovery time of 2$\mu$s while the quiescent current is below 14$\mu$A, overall achieving competitive state-of-art performance.