On-Chip Quantization- and Correlation-Robust Jitter Measurement for Low Phase Noise and High Frequency Oscillators

Abstract

For on-chip oscillator phase noise characterization and monitoring a common technique is the measurement of the equivalent cycle-to-cycle jitter. In this letter we show that the quantization introduced to the recorded jitter by the measurement with a time-to-digital converter can be prohibitive for calculating the phase noise, especially at high oscillation frequencies and for spectrally pure oscillators. A second drawback of this method is that supply voltage noise can mask the phase noise due to intrinsic device noise. To avoid these limitations, we investigate an approach where the oscillator under test is compared to an identical replica. The resulting time difference measurements are introduced as delta jitter. The validity of the method is proven in simulation and measurement of an on-chip jitter measurement macro designed in 16 nm FinFET CMOS technology. The measurement results indicate both robustness against quantization error and a self-canceling of correlated influences on phase noise in delta jitter measurements.