An 80mA Capacitor-Less LDO with 6.5µA Quiescent Current and No Frequency Compensation Using Adaptive-Deadzone Ring Amplifier

This paper presents a capacitor-less low dropout (LDO) regulator that requires no frequency compensation, with the use of an adaptive-deadzone ring amplifier. Due to the dynamic behavior of the ring amplifier depending on the input voltage, the proposed LDO features a hybrid (digital or analog) operation and achieves both fast transient response and high output accuracy with a low quiescent current. Moreover, an adaptive deadzone biasing scheme is employed to ensure high stability for a wide range of load current operating conditions. A 1V LDO prototype with 80mA maximum load current is implemented in a 0.18μm CMOS process, consuming only a quiescent current of 6.5μA with a dropout voltage of 90mV. It achieves 172-432ns settling time for load current transitions between 1mA and 81mA. The active area is 0.1mm ² .