All-Digital Background Calibration Technique for Offset, Gain and Timing Mismatches in Time-Interleaved ADCs

This paper presents a method for all-digital background calibration of multiple channel mismatches including offset, gain and timing mismatches in time-interleaved analog to digital converters (TIADCs). The averaging technique is used to remove the offset mismatch at each channel. The gain mismatch is calibrated by calculating the power ratio of the subADC over the reference ADC. Timing skew is compensated by using Hadamard transform for error correction and least mean squares (LMS) algorithm for estimation of the clock skew. The performance improvement of TIADCs employing these techniques is demonstrated through numerical simulations.