An adaptive calibration technique of timing skew mismatch in time-interleaved analog-to-digital converters

Because of the exponential increase of sampling rate, time-interleaved analog-to-digital converter (TIADC) has a fast growth in the high-speed applications. However, the channel mismatch error is a serious challenge for the performance of TIADC. In this article, we address the timing skew mismatch error and propose a novel adaptive calibration method. The principle and operating process of the calibration algorithm are explained. To validate the proposed technique, we designed a four-channel TIADC-based digital oscilloscope with a sampling rate of 10 GS/s. Based on this instrumentation platform, (i) calibration algorithm was implemented by hardware; and (ii) a test platform consisting of advanced instruments and tools was setup to testify the effect and robustness of proposed algorithm. Moreover, the technical details of instrumentation are described for the first time. The experimental results show that the calibration algorithm significantly suppresses the distortions due to timing skew mismatch error. The TIADC-based instrumentation achieves spurious-free dynamic range of 52.48 dB and effective number of bits of 5.83 bit, respectively. Besides, the complexity of the proposed algorithm is compared and discussed.