ABSTRACT
Along with basic feedback loop theory and common circuit implementations, the tutorial provides details on Integer/Frac-N, CMOS delay cell ring and LC VCO base PLL designs. Some details on current trends in dual loop control and digital PLL will be provided. Voltage or current controlled ring oscillators are critical design block for any PLL. Its ability to convert a relatively slow moving control voltage into a proportional frequency signal requires careful design. A programmable bank of MIM or MOM caps are used to calibrate/trim the center frequency. A bank of Varactors formed by NMOS device inside Nwell are used to provide continuous frequency tuning by the VCNT signal.
