A 200 mA low-area, low-noise, low-dropout linear regulator for monolithic active pixel sensors

To meet the low-material and low-noise requirements, the power supply of the monolithic active pixel sensors must be improved. This paper presents a built-in low-dropout (LDO) linear regulator to internally supply the analog power. A novel compensation strategy is proposed. Since a series RC network and an adaptively biased buffer are utilized, the location of the poles and zeros vary with that of the output pole. Employing one relative small compensation capacitor, the regulator is stable in the full range of load current. The regulator is designed and simulated in a standard 0.35 μm CMOS process. The chip area is 239 μm × 168 μm. The maximum load current of 200 mA can be obtained. The output spectral noise densities are 320 nV/ V Hz and 110 nV/ V Hz at 100 Hz and 1 kHz, respectively.