All-digital replica techniques for managing random mismatch in time-to-digital converters

We propose replica techniques with statistical post processing to improve integral non-linearity (INL) and code distribution performance of time-to-digital converters (TDC). We consider three different types of TDC namely: vernier delay line, multi-resolution, and ring oscillator based. We show that using a replica delay line with additional digital processing at the output, one can achieve better INL and code distribution (at every code) in each of the TDC architectures. The quantum of improvement is only limited by the additional hardware that is to be added, and can be traded for arbitrarily high improvements in INL and code distribution.