2.4 GHz-band ultra-low-voltage class-C LC-VCO IC in 65 nm CMOS technology

A novel LC-VCO IC is proposed to achieve low-voltage low-power operation even at a supply voltage below the threshold voltage. The LC-VCO consists of a VCO circuit, a power detector circuit and a comparator circuit. A feedback loop consisting of the power detector and the comparator can control the bias condition of the VCO. The LC-VCO IC has been designed, fabricated and fully evaluated using 65 nm CMOS technology. The fabricated VCO IC exhibits a measured phase noise of -111 dBc/Hz at 1 MHz offset from the 2.43 GHz carrier frequency at an operation voltage of only 0.3 V.