A 30-mA CMOS low dropout regulator for WiMAX analog front ends with 50 dB PSRR at 10 M Hz

While the application space for WiMAX has seen fast growth in recent years, on-chip digital circuits and high frequency switching converters have resulted in power supply noise with high frequency spectral content, which jeopardizes the reliability of sensitive WiMAX analog front ends. As a cost-effective solution, this paper presents a low dropout (LDO) regulator design, which achieves high PSRR at 10 MHz. The LDO is implemented and verified in a CMOS 0.25-μm process. With a 3-V input power supply, it provides a 2.8-V regulated output with a PSRR of 76 dB at 1 kHz and 50 dB at 10 MHz. The target maximum load current is 30 mA for this application.