External Cleanup PLL Closed-Loop Stability Analysis and Phase Noise Consideration

Don Pakbaz describes the analysis of an external Phase-Locked Loop (PLL) used as a cleanup PLL with High-Speed Serial (HSS) link to calculate system overall peaking and stability for three PLLs chained. The frequency domain transfer function of PLLs are modeled using hardware data and RF Toolbox™. The transfer function of PLLs then cascaded to calculate phase margin and gain margin using Control System Toolbox™. Time domain step response and jitter of overall system also evaluated using MATLAB^® and Simulink^®.