Impact of random channel mismatch on the SNR and SFDR of time-interleaved ADCs

Abstract

Using several ADCs (Analog to Digital Converters) in parallel with convenient time offsets is considered as an efficient way to push the speed limits of data acquisition systems. However, a serious drawback of this time-interleaving technique is that any mismatch between the channels will damage the precision. This paper gives a probabilistic description of the problem, studying the impact of time skews, gain and offset mismatches. The Probability Density Function (PDF) of both Signal-to-Noise Ratio (SNR) and Spurious-Free-Dynamic Range (SFDR) are explicitly calculated, giving access to important statistical parameters. It is shown that the SNR and SFDR dispersion should not be neglected in making practical considerations for design decisions.