A 74.6GHz–83.6GHz digitally controlled oscillator with 370kHz frequency resolution in 65nm CMOS

Abstract

All-digital PLLs promise flexible and precise FMCW radar signal generation for 77GHz radar applications. Such PLLs require digitally-controlled oscillators (DCO) with wide frequency tuning range (FTR) and high resolution to address a range of applications and low phase noise requirements. In this work, novel resonator structures with fine capacitance/inductance switching are embedded in a wide FTR common-source Colpitts DCO to achieve <1MHz DCO frequency resolution at 78GHz. The proposed structures also reduce dependence on switch-position for frequency step size, simplifying calibration. The DCO implemented in 65nm CMOS occupies 0.1mm2 and consumes 15.6mW to achieve 74.6GHz–83.6GHz FTR (11.4%) with 370kHz resolution, phase noise of −115dBc/Hz at 10MHz offset at 80GHz and state-of-the-art mm-wave DCO FoM-T of −182dBc/Hz.