A Voltage Controlled Oscillator with Tuning Gain Linearization and Automatic Frequency Calibration

A voltage-controlled oscillator (VCO) with automatic frequency calibration (AFC) and a linearized tuning gain (Kvco) for the phase noise optimization of the phase-locked loop (PLL) frequency synthesizer is presented in this paper. The proposed AFC module possesses a recalibration function to eliminate the impact of supply voltage and temperature (VT) variations on the PLL spurs. Designed in 40-nm CMOS LP process, the post-layout simulation results show that VCO achieves a frequency tuning range of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$4. 51\sim 5.39$</tex> GHz (17.58<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">%</sup>), with the variation of the Kvco less than 9.01% across <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$0.2 \sim 0.9 ~\mathrm{V}$</tex> tuning range in each single frequency band. At 4.8 GHz, the phase noise is -124.6 dBc/Hz@lMHz, and the figure of merit (FoM) is 186.6 dBc/Hz@1MHz. The power consumption is less than 16 mW under 1.1 V supply voltage. With an 80 MHz reference, the calibration time for the AFC ranges from 2.75 to 13.75 <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\mathrm{\mu}\mathrm{ s}$</tex>.