A 10 nA Ultra-Low Quiescent Current and 60 ns Fast Transient Response Low-Dropout Regulator for Internet-of-Things

Ultra-low quiescent current ( $I_{Q}$ ) low-dropout regulator is the only solution for compact size Internet of Things (IoT) electronic devices. This paper presents an ultra-low $I_{Q}$ low dropout regulator, including low $I_{Q}$ error amplifier (EA) compensated by the adaptive current control (ACC), low leakage feedback network, low $I_{Q}$ current comparator, analog transient enhancement (ATE), and digital transient enhancement (DTE). The chip was fabricated in a standard $0.5~\mu \text{m}$ CMOS process. Measurement results show the current peak efficiency of the LDO is as high as 99.99%. Besides, owing to ATE and DTE circuits, when the load current changes from 1mA to 50mA with a 10 ns edge time, the measured undershoot and overshoot voltages are 75 mV and 50 mV, respectively, with the recovery time ( $T_{R}$ ) of 60 ns and 80 ns, respectively, where the best 0.003 ps FoM is achieved.