Reduction of up-converted flicker noise in differential LC-VCO designed in 32nm CMOS technology

This paper deals with the design of LC Voltage Controlled Oscillator (LC-VCO) for GSM applications, implemented in a state-of-the-art 32 nm Planar CMOS technology. A standard VCO is compared with a topology featuring tail decoupling, which, to best of our knowledge, is used for the first time for a wide tuning-range application (i.e. 700 MHz centered at 3.65 GHz). The Decoupled VCO significantly reduces the Phase-Noise, up to 9 dB, by lowering the impact of the flicker noise introduced by the switching-pair on the 1/f³ region, with comparable current consumption and tuning-range with respect to the standard VCO.