Behavioral modeling of charge pump phase locked loops

The CP-PLL is a typical mixed signal device; there is no general theory to describe exactly the dynamics of its nonlinear transient. Many models have been presented to model the behavior of the PLL. A discrete linear model, a discrete nonlinear model and an event-driven model of the second order PLL have been proposed. A comparison of these models with a transistor level model shows that the event-driven model is the most accurate. Moreover, the computational effort of these models for a given accuracy is significantly less than a full SPICE simulation.