An Application of the Second-Order Passive Lead–Lag Loop Filter for Analog PLLs to the Third-Order Charge-Pump PLLs

A second-order passive lead-lag loop filter for analog phase-locked loop (PLLs) is modified in this paper for the third-order charge-pump PLLs (CPPLLs). The analysis shows that the CPPLL employing the modified loop filter results in smaller area, lower power consumption, or better noise performance than the CPPLL employing the conventional loop filter.