Analysis and design of analog-based voltage controlled oscillator linearization technique

This paper analyzes an analog technique for VCO linearization based on a switched-capacitor feedback loop. The analysis covers both inversely and directly proportional VCOs. Based on this analysis, design criteria for determining the best loop parameters are presented using a look-up table. In addition, the tradeoffs between the linearized VCO tuning range, dynamic range, and loop settling speed are marked out. Simulation results show that the above analysis allowed the design of a linearization loop which improved the non-linearity of a 2 GHz tuning range VCO from 8% to 0.4%.