All-Digital Background Calibration for Time-Interleaved ADC Using Differential Fir Filter

An all-digital background calibration algorithm based on differential filter for timing mismatch is presented. By crossing and recombining every two channels of the M-channel TI ADC, a new M/2-channel TI ADC is obtained and then calibrated by timing mismatch estimator and differential filter. Repeat the process described above until one output channel is formed. A 4-channel TI ADC with only timing mismatch is used to simulate and verify the proposed algorithm. The simulation results demonstrate the effectiveness of this technique, in which the SNDR and the SFDR performance of the TI ADC are improved from 56.3dB, 60.2dB to 81.0dB, 94.5dB with the input frequency being 0.06 fs, respectively.