Modeling and synthesis of wide-band switched-resonators for VCOs

A two-level switched resonator model for synthesizing a wide-tuning range LC VCO is described. Viable resonator design styles are selected for achieving broadband frequency synthesis. A simple, generalized model is developed for design space exploration. Using this model, based on the performance specifications, a resonator style is selected. Also, the performance specifications are translated to individual resonator components. At the second level, detailed models for the resonator components are developed. The resonator is then designed and simulated based on these models. As an example, a wideband VCO using a new inductor switching technique is explored. Simulations performed in a 0.18 μm CMOS process achieved a tuning range from 3.3S to 8.34 GHz while exhibiting phase noise between -107 and -119 dBc/Hz at 1 MHz offset over the entire range. The VCO core dissipated 1.9 to 8.3 mW power using a 1.8-V supply.