ABSTRACT

Currently, the PLL is widely used in communications, radar, test equipment and other systems, and VCO is the most sensitive block to supply noise and be the performance limiting factor for low-voltage PLL (Kim et al., 2016), which directly generates the output feedback signal.The operating frequency range of theVCO determines the capture range of the charge pump PLL, and its noise suppression ability determines the noise performance of the PLL. Therefore, the performance of the VCO is directly related to the performance of the whole PLL and the ability to work properly.