A high PSR over wideband frequency range low dropout voltage regulator

An improved low dropout regulator (LDO) with high power supply rejection (PSR) over wideband frequency range is presented in this paper. The proposed design employs the supply ripple subtraction and high-pass filtering to achieve high PSR performance. The proposed LDO is fabricated by TSMC 0.35 μm 2-poly 4-metal CMOS process. The simulation results for a 50-mA load current show that the PSR is -69 dB at 10 kHz, -59 dB at 100 kHz, -53 dB at 1 MHz, and -58 dB at 10 MHz. The results show that the proposed design is suitable for switching mode DC-DC converter and SoC applications. The active area of the LDO is 270 × 320 μm².