SPLIT-ADC BASED DIGITAL BACKGROUND CALIBRATION FOR TIME-INTERLEAVED ADC

摘要

A novel Time-Interleaved Analog-to-Digital Converter (TIADC) digital background calibration for the mismatches of offsets,gain errors,and timing skews based on split-ADC is proposed.Firstly,the split-ADC channels in present TIADC architecture are designed to convert input signal at two different channel sampling rates so that redundant channel to facilitate pair permutation is avoided.Secondly,a high-order compensation scheme for correction of timing skew error is employed for effective calibration to preserve high-resolution when input frequency is high.Numerical simulation performed by MATLAB for a 14-bit TIADC based on 7 split-ADC channels shows that Signal-to-Noise and Distortion Ratio (SNDR) and Spurious Free Dynamic Range (SFDR) of the TIADC achieve 86.2 dBc and 106 dBc respectively after calibration with normalized input frequency near Nyquist frequency.