A Low-Power Fully Digital Time-to-Digital Converter Based on SMIC 55nm Chip

Highly precision time interval measurement systems are used in many fields, among which TDC is a chip specialized in timing, because of its ability to achieve picosecond time interval measurement units, it is widely used in high-speed and high-energy fields such as time flight, LIDAR, PET, and so on. In the digital field, the solution for TDC is usually the interpolation method, i.e., the system clock is interpolated using multiple delay cells. TDL is a unidirectional chain with n delay cells, with outputs after each delay cell. In theoretical conditions, when 1 bit of system clock passes through the TDL, n bit signals will be obtained, and each signal passes through one more delay cell than the previous signal. The article is based on the SMIC 55nm chip implementation, using a combination of coarse and fine methods to achieve a large number of 64-channel high-precision TDC design for attempting to apply in the PET field.