A 90nA quiescent current 1.5V–5V 50mA asynchronous folding LDO using dual loop control

This paper presents a 90 nA quiescent current 1.5V–5.0V LDO regulator in a 0.35 um BiCMOS process. A new dual-loop (asynchronous digital loop and an analog loop) LDO is proposed. The digital loop (D-Loop) boosts the loop response speed under fast switching clock frequencies and the analog loop (Α-Loop) provides a clean output voltage with an ultra-low current consumption. The prototype IC achieves 90 nA of quiescent current during steady state with a power supply of up to 5.0 V. It has a drop-out voltage of 200 mV and a 50 mA output current capability. This prototype is implemented using a 0.35 um BiCMOS process and the active chip area is 0.25 mm2.