Real-Time Digital Background Calibration Technology for Integral Nonlinearity of Analog-to-Digital Converters

This article presents a real-time digital background calibration method for integral nonlinearity (INL) errors in analog-to-digital converters (ADCs) based on the conventional look-up table (LUT) technology. This method effectively calibrates INL without requiring additional quantization bits, making it ideal for high-speed acquisition systems with stringent real-time demands. Additionally, the article introduces an INL error estimation method that leverages clipped signals. The proposed calibration and estimation method was tested on an 8-bit, 2.5 GSPS sampling rate ADC, and the results demonstrated a reduction in calibrated INL error from −1.4 to 2.9 least significant bits (LSBs) to ±0.1 LSBs and an increase in spurious free dynamic range (SFDR) from 46.21 to 64.70 dB.