Frequency-Aware PPV: A robust phase macromodel for accurate oscillator noise analysis

Perturbation projection vector (PPV) is an established technique for oscillator phase noise analysis; However, the PPV method significantly loses accuracy when circuits have large time constants, resulting in over-estimation of oscillator phase noise. In this paper, we show the problem of the PPV phase equation that it ignores the dynamics of oscillator frequency responses, and propose an improved PPV technique: Frequency-Aware PPV (FW-PPV). Using the FW-PPV technique, we derive analytical phase noise equations, which work accurately for all oscillators, especially for oscillators with large time constants. We apply the proposed technique on real oscillator circuits, and compare the results to Cadence Spectre RF. Simulation results show that our method has better accuracy than previous approaches.