5.11 A 65nm inverter-based low-dropout regulator with rail-to-rail regulation and over −20dB PSR at 0.2V lowest supply voltage

Ultra-low-voltage operation is highly demanded in a system that adopts the DVFS scheme, e.g., a portable device that sustains days-long standby with a tiny battery. Such a system usually embeds modules that have specific minimum supply voltages. Point-of-load low-dropout regulators (LDOs) are used to power these modules as per the required applications, from a global supply rail Vdd. The global Vdd is noisy and can be varied within a wide range, which adds to the difficulty of designing LDOs in such applications.