Two-Step Subranging ADC Architecture

摘要

First and second track and hold stages track and store an input voltage for a sample of an analog input signal. A coarse reference ladder provides a plurality of coarse references. The coarse reference ladder includes a first coarse reference and a second coarse reference ladder. A coarse ADC performs a first comparison of the input voltage and the coarse references and outputs a coarse output based on the first comparison. A switch matrix includes switches and is configured to close a switch corresponding to a coarse reference based on the coarse output. A fine reference ladder provides fine references. A fine ADC performs a second comparison of the input voltage and the fine references and outputs a fine output based on the second comparison. Logic outputs a digital output for the sample of the analog input signal based on the coarse output and the fine output.