A Mixed Sample-Time Error Calibration Technique in Time-Interleaved ADCs

Abstract

Sample-time error between channels degrades resolution of time-interleaved analog-to-digital converters (TIADCs). A calibration method implemented in mixed circuits with low-complexity and fast-convergence is proposed in this paper. The algorithm for detecting sample-time error, which is widely applied to wide-sense stationary input signals, is based on correlation. The detected sample-time error is corrected by a voltage-controlled sampling switch. Experimental result of a 2-channel 200-MS/s 14-bit TIADC shows that the signal-to-noise-and-distortion ratio improves 19.1 dB, and the spurious-free dynamic range improves 34.6 dB for a 70.12-MHz input after calibration. The convergence time of the calibration is about 20000 sampling intervals.