Design and optimization of a low noise 2.4 GHz CMOS VCO with integrated LC tank and MOSCAP tuning

A 2.4 GHz LC voltage controlled oscillator is designed and optimized via linear programming and implemented in a 0.35 /spl mu/m RF BiCMOS process technology. Our design methodology provides an insight to choosing design variables given several constraints such as voltage swing, tuning range and start-up condition. The on-chip spiral inductors used are modeled and optimized by a 3D inductor simulator. The inversion mode MOSCAP tuning is used to achieve 26% of tuning range. The measured phase noise is -121 dBc/Hz, -117 dBc/Hz and -115 dBc/Hz at 600 kHz offset from 1.91 GHz, 2.03 GHz and 2.60 GHz carriers, respectively. The VCO dissipates only 4 mA from a 2.5 V supply voltage.

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