Design of a sub-1-V bandgap reference for low dropout regulator in SR-ALF-VCOs

Full-swing voltage-controlled oscillators (VCOs) are very sensitive to supply noises and require supply regulators with increased supply voltages, which may entail more power consumption. Further, in a phase-locked loop (PLL) with a conventional second-order passive-loop filter (PLF), PLL output frequency range is restricted by the compliance range of the charge pump output voltage (VCP) even though supply-regulated VCOs (SR-VCO) can provide a wider frequency range. In order to solve these problems, VCP be separated from the VCTRL using the low dropout regulator (LDO). This paper proposes a bandgap reference (BGR) of 0.61V output voltage for low dropout regulator of in supply-regulated active-loop filter VCOs (SR-ALF-VCO).