ADC device and method for converting an analog signal to a digital signal

Abstract

An ADC device includes a first stage that has an input that receives an analog signal and an output that transmits a first digital signal based on the analog signal. The first stage includes a SAR that receives the analog signal and performs successive approximations of the analog signal to provide the first digital signal. The SAR includes a passive switched-capacitor integrator that filters off low frequency white noise and integrates a residual signal that is based on comparisons controlled by the successive approximations of the analog signal to the analog signal to generate a filtered first stage quantization error. A second stage receives and converts the filtered first stage quantization error to a second digital signal, and the digital filter combines the first digital signal and the second digital signal to provide a combined digital signal.

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