Low power and low phase noise VCO with dual current shaping for IoT applications

Abstract

In this paper, two low phase noise and power consumption VCO circuits, which are suitable for Internet of things (IoT) applications, are proposed. In the first structure, in order to have more control of the current consumption, the current shaping technique is used in the PMOS and NMOS biasing circuit. In the second structure, for increasing the oscillation amplitude and reducing the phase noise, independent biasing for the NMOS section is used. In both structures, to increase the frequency tuning range (FTR), without using a capacitor bank, the varactor is used in the biasing structure. In the first structure the supply voltage, output frequency, power consumption, and phase noise are 0.8 V, 2.44 GHz, 0.37 mW, and -117.5 dBc/Hz, respectively, but in the second structure, the supply voltage, output frequency, power consumption, and phase noise are 0.8 V, 2.44 GHz, 0.62 mW, and -120 dBc/Hz, respectively. It should be noted that the two structures are designed and simulated in 65-nm CMOS technology. Finally, the results show that the figure-of-merit for the first and second structures is --190 dBc/Hz and --190.2 dBc/Hz, respectively.