An external-capacitor-less high-PSR low-dropout regulator using an adaptive supply-ripple cancellation technique to the body-gate

This work presents an external-capacitor-less low-dropout regulator (LDO) that provides high power-supply rejection (PSR) at all low-to-high frequencies. Using the proposed adaptive supply-ripple cancellation (ASRC) technique, where the ripples copied from the supply are injected adaptively to the body-gate, the PSR-hump of conventional LDOs can be suppressed significantly. The proposed LDO was fabricated in a 65-nm CMOS process, and the measured PSRs were less than -36dB at all frequencies from 10kHz to 1GHz, despite changes in a load current (Zl) and a dropout voltage (Fdo).