An analog-digital hybrid fine interpolation TDC with uncontrolled delay line and calibration approaches

With the development of physics experiments, many detectors utilize a time-to-digital converter (TDC) to achieve a high-precision Time-of-Arrival (ToA) measurement. An analog-digital hybrid fine interpolation TDC is proposed to achieve high time precision in this paper. The TDC consists of an analog-digital hybrid fine interpolator and a digital module. The analog-digital hybrid fine interpolator is composed of an uncontrolled delay line, switches and source followers. This paper discusses the theory of operation of the proposed architecture and the calibration approaches. A prototype ASIC has been designed in a commercial 180 nm BCD process. Only post-layout simulation results are presented in this paper. The simulation results show that the precision of the TDC is about 5.76 ps, the maximum bin width is 15 ps and the dynamic range of 2.8 ns with an external ADC at the terminal of the analog.