Optimization of SiGe HBT VCOs for wireless applications

This paper describes the optimization of phase noise performance in fully integrated SiGe HBT differential LC-tuned voltage-controlled oscillators (VCOs) for wireless applications. An accurate expression for phase noise in SiGe HBT LC-tuned VCOs is presented which takes the nonlinear operation of the oscillator into account. Design methods are shown which minimize the different sources of phase noise toward the intrinsic limit set by the resonator quality factor. A set of 2 GHz SiGe HBT VCOs have been implemented in a 0.5 /spl mu/m, 47 GHz SiGe BiCMOS process to provide experimental verification of the benefits of the design methods presented in this paper.