A Self-Calibrated Bang–Bang Phase Detector for Low-Offset Time Signal Processing

This brief describes a self-calibrated bang-bang phase detector that has been implemented in a delay-locked loop (DLL) stabilized time-to-digital converter for high-energy physics applications. A two-state architecture is proposed, with a dedicated calibration state that measures the internal static phase offset and compensates for this offset in the other measurement state. The calibration is transparent to the DLL, runs continuously to compensate for radiation induced drifts, and shows a measured static phase offset variation of only 0.5 ps over different samples. The circuit has been designed and processed in a 40-nm CMOS technology.