VLSI Implementation of VCO

voltage controlled oscillator

The phd thesis on Design and Characterization of RFIC Voltage
Controlled Oscillators in Silicon Germanium HBT
and Submicron MOS Technologies

free available at
http://scholar.lib.vt.edu/theses/available/etd-08092005-120515/unrestricted/Adam…

Advances in wireless technology have recently led to the potential for higher data
rates and greater functionality. Wireless home and business networks and 3G and
4G cellular phone systems are promising technologies striving for market acceptance,
requiring low-cost, low-power, and compact solutions. One approach to meet these
demands is system-on-a-chip (SoC) integration, where RF/analog and digital circuitry
reside on the same chip, creating a mixed-signal environment. Concurrently, there
is tremendous incentive to utilize Si-based technologies to leverage existing fabrication
and design infrastructure and the corresponding economies of scale. While the
SoC approach is attractive, it presents major challenges for circuit designers, particularly
in the design of monolithic voltage controlled oscillators (VCOs). VCOs
are important components in the up or downconversion of RF signals in wireless
transceivers. VCOs must have very low phase noise and spurious emissions, and be
extremely power efficient to meet system requirements. To meet these specifications,
VCOs require high-quality factor (Q) tank circuits and reduction of noise from active
devices; however, the lack of high-quality monolithic inductors, along with low noise
transistors in traditional Si technologies, has been a limiting factor.