Linearity Boosting Technique with Adaptive Sampling Switch Assisted by Signal Prediction for Multi-Channel ADCs in Standard CMOS Process

A linearity boosting technique that samples the signal with adaptive sampling switch assisted by signal prediction is presented in this work for multi-channel ADCs. The linearity and accuracy are effectively improved when the number of on switches is dynamically adjusted according to the result of first-order signal prediction based on the ADC's digital output. A compact model is built to optimize the grouping scheme of the sampling switches. By dividing the sampling switch into 16 elements, the spurious-free dynamic range (SFDR) and signal-to-noise-and-distortion ratio (SNDR) are improved by 13 and 4.9 dB, respectively, for a 12-bit, 50-MSPS ADC in 65-nm CMOS process. The proposed linearity boosting technique can be realized in standard CMOS process without using bootstrapped switch or dynamic substrate bias technique, therefore it is very suitable for low-cost systems, especially for multi-channel applications.