Broadband Research And Design Of Inductor-capacitor Voltage-controlled Oscillator

The rapidly progress on wireless-communication and CMOS technology makes more and more radio frequency (RF) systems integrated in a System-On-a-Chip (SOC) to be possible. One of them is the RF TV tuner for digital High-Definition Television (HDTV). With the development of digital TV industry, the TV tuner system has gained widely attention and deeply research.As an important part of the frequency synthesizer, Voltage-Controlled Oscillator (VCO) is one of the critical circuits in TV tuner system. This work focuses on the wideband LC VCO design for TV tuner application, including circuit theory analysis, chip implement and measurement.Firstly, a double-conversion low-IF TV tuner system architecture is presented, from which the wideband VCO specification is derived. And the base LC-VCO architecture is researched, theory analysis of the power, phase noise and tuning gain are presented in detailed.Secondly, the wideband VCO design and optimize methodology is presented. Based on the theory analysis, a relationship between the wide frequency range and tuning gain is researched.The design of fully-differential wideband VCO with stable tuning gain is the principal part of this paper. A switched varactor array in a single-inductor VCO is proposed to suppress the tuning gain (KVCO) fluctuation. By choosing the unit varactor of the array carefully, the KVCO variation can be significantly reduced.Finally, the chip design and measurement results are presented. The chip achieves good performance in the required frequency band, and can be satisfy the TV tuner application.