ABSTRACT
The analog-to-digital converter (ADC) is one of the most popular devices in electronics, but the time-to-digital converter (TDC) is a not-so-popular device. The TDC has been used mostly in scientific experiments to measure the lifetime of nuclei, the quenching time of fluorescence, the drift time of ions, the time of flight (ToF) of moving particles, and so on. In the meantime, the application of the TDC is becoming wider and wider, and many people are willing to know more about the TDC. Unfortunately, there are only a handful of references: (a) some commercial TDC devices, (b) review papers [1,2], and (c) a book [3] about TDC. This is mainly because the TDC circuit is mostly custom implemented in application-specific integrated circuits (ASICs) or field-programmable gate array (FPGA).
