Hardware implementation of all digital calibration for undersampling TIADCs

Abstract

This paper presents a practical implementation of all digital calibration algorithm for the gain and timing mismatches in undersampling Time-Interleaved Analog-to-Digital Converter (TI-ADC). A new Least Mean Square (LMS) based detection scheme is proposed to increase convergence speed as well as to enhance the estimate accuracy. Monte Carlo simulations for a four-channel undersampling 60 dB SNR TI-ADC clocked at 2.7 GHz show that SFDR can achieve approximately 90 dB SFDR within the stable point of the channel mismatch coefficients over the first three Nyquist Bands. The proposed architecture is implemented and validated on the Altera FPGA DE4 board. The synthesized design consumes a few percentages of the hardware resources of the FPGA chip and work properly on a Hardware-In-the-Loop emulation framework.