Research And Design Of New Type Of Charge Pump PLL

With the rapid development of communication industries, PLL has been widely used inmany products, such as wireless communication, radar system and digital TV etc. The functionsof frequency multiplication and frequency division of PLL are used in test field as well.The symmetric CPPLL with silter0.18u process and650MHz center frequency is used inthe design of this thesis, which belongs to the cooperative project of my mentor and Teralanesemiconductor inc. In this thesis, the history and current development of PLL are firstlyintroduced. Then a linearized model of CPPLL is proposed to analyze parameters’ effects on thePLL system. The third session is the specific circuit design. In this session different schemes ofeach module are specifically analyzed and the best one is chosen to be used in the design. Asymmetric charge pump is used in this design. The simulation demonstrates that the symmetriccharge pump’s current mismatch of charge and discharge is extremely small and the swing ofcontrol voltage meets the requirement. The VCO without tail current source can increase theoutput signal swing of VCO. A positive feedback flip-flop is designed to accelerate the switchspeed of output signal. The final session is simulation of sub-modules and system. Thesimulation shows that the center frequency of PLL is650MHz, the duty cycle of output signalwaveform is49.6%and the output frequency ranges from420MHz to880MHz. The simulationresult shows that the designed PLL meets the requirement.