A 0.5-V 3.6/5.2 GHz CMOS multi-band LC VCO for ultra low-voltage wireless applications

In this paper, an ultra low-voltage multiband CMOS VCO based on tunable band-limited negative resistance approach is presented. The proposed technique eliminates the need for switching elements that are connected directly to the tank and limit the tuning range and phase noise performance. The oscillator draws a current of 6mA from 0.5V supply with a phase noise of −117dBc/Hz at 1MHz offset from 3.6GHz carrier. For the high frequency band, it draws 4mA from the same supply with a phase noise of −117dBc/Hz at 1MHz offset from 5.2GHz carrier.