Explicit analysis of channel mismatch effects in time-interleaved ADC systems

A time-interleaved A-D converter (ADC) system is an effective way to implem ent a high-sampling-rate ADC with relatively slow circuits. In the system, several channel ADCs operate at interleaved sampling times as if they were effectively an effective way to implement a high-sampling rate ADC with rel atively slow circuits. In the system, several channel ADCs analog CK1 opera te at interleaved sampling times as if they were effectively a single ADC o perating at a much higher sampling rate. However, mismatches such as offset , gain mismatches among channel ADCs as well as timing skew of the clocks d istributed to them degrade S/N of the ADC system as a whole. This paper ana lyzes the channel mismatch effects in the time-interleaved ADC system. Prev ious analysis showed the effect for each mismatch individually, however in this paper we derive explicit formulas for the mismatch effects when all of offset, gain and timing mismatches exist together. We have clarified that the gain and timing mismatch effects interact with each other but the offse t mismatch effect is independent from them, and this can be seen clearly in frequency domain. We also discuss the band width mismatch effect. The deri ved formulas can be used for calibration algorithms to compensate for the c hannel mismatch effects.