A low noise, 1.28µA quiescent regulator with broadband high PSR for micropower sensors

Abstract

An ultra-low power, low-noise, high power supply rejection (PSR) op-ampless regulator is presented in this paper. It uses a native composite power transistor plus a sandwich on-chip native capacitor in the pre-regulator to enhance broadband high PSR performance. Besides, a pseudo-resistor based low-pass filter is used to reduce the Brokaw's voltage regulator circuit noise. Realized using GlobalFoundries 1.8V/3.3V CMOS 0.18μm process, the regulator gives a mean output 0.992V for 8 samples while occupying a silicon area of 0.095mm2. It consumes only 1.28μA and drives a maximum output current of 2mA. The measured output noise is 80.1nV/vHz at 1kHz and 14.2nV/vHz at 100kHz while the integrated output noise over 10Hz-100kHz bandwidth is 13.88μVrms. The measured PSR is -79.1dB @ 10Hz, -55.3dB @ 1MHz and -41.6dB @ 10MHz. The proposed regulator is useful for sensor circuit applications using energy harvesting power source.