A Low-Voltage Class-D VCO with Implicit Common-Mode Resonator Implemented in 55 nm CMOS Technology

This paper presents a Class-D voltage-controlled oscillator (VCO) with a hybrid switch capacitor array. In order to reduce the phase noise of the oscillator, an implicit common-mode resonance technique is used, effectively suppressing the conversion of power supply noise to VCO phase noise. At the same time, due to the use of a transformer in implicit common-mode resonance technology, the core area of the oscillator is not significantly increased compared with the traditional Class-D VCO. Based on the proposed technology, the proposed VCO exhibits lower phase noise compared to the original Class-D VCO, and also has many different advantages compared to low-voltage VCOs produced by similar technological processes. The proposed VCO was designed in a 55 nm CMOS process. Simulation results show that this VCO has an operating range from 4.36 to 6.43 GHz, resulting in the frequency tuning range (FTR) of 38.5%. In addition, its power consumption was 3.46 mW, the phase noise at 4.36 GHz was -124.2 dBc/Hz@1 MHz, and the figure of merit (FoM) was -191.6 dBc/Hz@1 MHz. The core area is 0.15 mm(2).