PSR Enhancement Through Super Gain Boosting and Differential Feed-Forward Noise Cancellation in a 65-nm CMOS LDO Regulator

This paper presents a 65-nm CMOS low-dropout (LDO) regulator employing a super gain amplifier (SGA) and differential feed-forward noise cancellation to maximize the power supply rejection (PSR). The SGA in the error amplifier is augmented by a positive feedback current mirror, and this SGA boosts the loop gain through local negative feedback. With 1.2 V supply voltage, the LDO regulator has a 200 mV drop-out voltage and the ability to handle a maximum 25 mA load current. The measurement results show a -47 dB PSR ratio of up to 10 MHz and dc load regulation under 1 mV for full load current change.