Title :
Concepts and methods in optimization of integrated LC VCOs
Author :
Ham, Donhee ; Hajimiri, Ali
Author_Institution :
Dept. of Electr. Eng., California Inst. of Technol., Pasadena, CA, USA
fDate :
6/1/2001 12:00:00 AM
Abstract :
Underlying physical mechanisms controlling the noise properties of oscillators are studied. This treatment shows the importance of inductance selection for oscillator noise optimization. A design strategy centered around an inductance selection scheme is executed using a practical graphical optimization method to optimize phase noise subject to design constraints such as power dissipation, tank amplitude, tuning range, startup condition, and diameters of spiral inductors. The optimization technique is demonstrated through a design example, leading to a 2.4-GHz fully integrated, LC voltage-controlled oscillator (VCO) implemented using 0.35-μm MOS transistors. The measured phase-noise values are -121, -117, and -115 dBc/Hz at 600-kHz offset from 1.91, 2.03, and 2.60-GHz carriers, respectively. The VCO dissipates 4 mA from a 2.5-V supply voltage. The inversion mode MOSCAP tuning is used to achieve 26% of tuning range. Two figures of merit for performance comparison of various oscillators are introduced and used to compare this work to previously reported results
Keywords :
CMOS analogue integrated circuits; UHF integrated circuits; UHF oscillators; circuit optimisation; circuit tuning; inductors; integrated circuit noise; phase noise; voltage-controlled oscillators; 0.35 micron; 2.4 GHz; 2.5 V; 4 mA; MOS transistors; diameters; graphical optimization method; inductance selection; integrated LC VCOs; inversion mode MOSCAP tuning; noise properties; oscillator noise optimization; phase noise; power dissipation; spiral inductors; startup condition; tank amplitude; tuning range; Constraint optimization; Design optimization; Inductance; Mechanical factors; Optimization methods; Phase noise; Power dissipation; Spirals; Tuning; Voltage-controlled oscillators;
Journal_Title :
Solid-State Circuits, IEEE Journal of