A Novel Two-Stage Timing Mismatch Calibration Technique for Time-Interleaved ADCs

This brief proposes a timing mismatch calibration for time-interleaved analog-to-digital converters (TI ADCs) with the novel parallel correlation derivative (PCD) technique and two-stage analog–digital hybrid compensation. The PCD technique could solve the frequency-relevant problem caused by low correlation derivative in the precise skew calculation. Besides, the compensation scheme with an analog coarse correction and then the all-digital fine correction is used to cover a larger normalized skew range and bandwidth with maintained calibration performance. Compared to previous works on timing mismatch calibration, this work has improved accuracy with a larger effective bandwidth and a larger skew calibration range. The technique is applied in a four-channel 14-bit 3 GS/s ADC model to verify its effectiveness. Simulation results show that it increases the SNDR and SFDR from 31.02 and 32.87 to 54.40 and 93.49 dB at
${f}_{\text {in}}\,\,=\,\,0.99{f}_{s}$
and maintains good performance in the first three Nyquist bands.