Deign and Analysis of a 3.58-4.46 GHz High Linearity and Low noise CMOS LC-tank VCO

Design and analysis of a highly linear-tuning and low phase noise 40nm CMOS LC-tank Voltage-controlled oscillator was presented in this paper. The phase noise of LCVCO is reduced by complementary CMOS cross coupled topology and tail current source filtering technology. Meanwhile, a linear tuning array composed of diode-connected NMOS devices was used to optimize the linearity of sub-band frequency tuning curve, The range in which MOS variable bank decreases with the control voltage is used to compensate the range in which MOS variable bank increases with the control voltage. For LCVCO, the nonlinearity of frequency rising with control voltage is used to compensate the nonlinearity of frequency falling with control voltage. The LCVCO output frequency covers 3.58GHz-4.46GHz,while increasing linearity, the frequency tuning range of sub-band is not reduced. When the control voltage between 0.2V-1.2V,the KVCO variation only 3.2%.Phase noise of 119.92 dBc/Hz at 1MHz offset from 4.46GHz, the power consumption of core circuit is 3.42mA under 1.2V power supply.