A capacitor-free high PSR CMOS low dropout voltage regulator

This paper presents a capacitor-free CMOS low dropout voltage regulator which has high PSR performance and low chip area. Pole splitting and gm boosting techniques are employed to achieve good stability. The capacitor-free chip LDO was fabricated in commercial 0.18 μm CMOS technology provided by GSMC (Shanghai, China). Measured results show that the capacitor-free LDO has a stable output voltage 1.79 V, when supply voltage changes from 2.5 to 5 V, and the LDO is capable of driving maximum 100 mA load current. The LDO has high power supply rejection about −79 dB at low frequency and −40 dB at 1 MHz frequency, while sacrifice of the LDO's active chip-area is only smaller than 0.02 mm2.