Various PLL circuits are highly important components of today’s electronic systems and appliances. The subject of my thesis work is the design of a VCO suitable for use in such PLLs.
In the first part of my thesis work, I cover the topics of the operation of PLL circuits, the theory and classification of oscillators, the main characteristics and implementation methods of VCOs, and the theory of noise in oscillators and their effects on applications.
Then, I present the design process of a ring and a Wien-bridge oscillator at schematic level, including the determination of device parameters and the verification of the design via simulation. I then select the topology to be further implemented based on the simulation results. Then, I examine the effect of nonlinearity within the Wien-bridge oscillator on phase noise using high-level modeling.
Finally, I present the details of the design process of the layout for the Wien-bridge oscillator, I present the finished layout and check its manufacturablity (DRC).
I designed the circuit on a 180-nanometer CMOS process, using the CADENCE design system. I used SPECTRE for performing simulations.