A Wide-Load-Range and Full-Spectrum Power Supply Rejection LDO for Wideband RF Transceiver Systems

This paper proposes a wide-load-range low-dropout regulator (LDO) using a rail-to-rail CLASS-AB CMOS buffer. This buffer enables the output-pole-dominant (OPD) LDO to support a broad load current range (ILOAD) from $100 \mu ~\mathrm{A}$ to 300 mA, while maintaining a phase margin (PM) above 60° and a power-supply rejection (PSR) better than −26 dB at 100 MHz. Over an input voltage range of 1.2 V to 1.4 V, the proposed LDO can always achieve excellent PSR at low frequencies. Additionally, the LDO minimizes undershoot and overshoot to below 10 mV.