A 3.3 GHz LC-based digitally controlled oscillator with 5kHz frequency resolution

This paper reports a LC-based digitally controlled oscillator (DCO) with an enhanced frequency resolution and an extended linear frequency tuning range. It has a center frequency of 3.3GHz and a frequency tuning range of 600MHz covered by 64 different frequency bands. Each frequency band has 2048 linear tuning levels with a frequency step of 5kHz. This DCO was implemented in 90nm CMOS and the measured frequency tuning characteristics are provided in this paper. The DCO exhibits a phase noise of −118dBc/Hz at 1MHz frequency offset. The DCO core consumes 2mA current from 1.2V supply.