Fast and high-precision VCO frequency calibration technique for wide-band frequency synthesizer

A fast and high precision VCO frequency calibration technique suited for wide-band PLL frequency synthesizer is reported in this article. The proposed frequency calibration adopts a quadrature-phase detection method which achieves very fast calibration time without degrading its calibration precision. 6-bit capacitor bank is used for the wideband VCO and LO frequency of the proposed wideband PLL is 9.75-11.5GHz. The proposed frequency synthesizer is simulated in 65nm CMOS technology, which favors high frequency digital circuits design. Clock frequency of calibration circuit is 700MHz. Total calibration time of the proposed technique is 3.4us and the frequency resolution is 8.3MHz.