A Background Timing Skew Calibration Technique in Time-Interleaved ADCs With Second Order Compensation

A background second order compensation calibration for timing skew in time-interleaved (TI) analog-to-digital converters (ADCs) is proposed in this paper. With an autocorrelation function applied, the sign of timing skew is acquired. And then a second order compensation calibration with Lagrange interpolation is employed to minimize the timing skew. Compared to the conventional calibration model, the proposed technique further reduces the residue errors caused by the insufficient first order compensation. Simulation results show that when timing skew is larger than 0.03 Ts, the second order compensation technique increases the SNDR and SFDR at least 7 dB and 12 dB compared to its first order counterpart. In addition, the proposed calibration technique is extendable to any number of channels in TI-ADC.