A quantizer includes a voltage reference network and a set of comparators coupled with the voltage reference network. The voltage reference network generates a plurality of reference voltages. Each of the comparators receives an input signal and produces a sequence of digital samples. The set of comparators includes first, second, and third subsets of comparators. Each comparator of the first subset includes a switched capacitor stage, each comparator of the second subset includes a preamplifier stage, and each comparator of the third subset includes a switched capacitor stage. The first and third subsets of comparators compares the input signal with reference voltages corresponding to the upper and lower voltage ranges of the input signal, and the second subset of comparators compares the input signal with reference voltages corresponding to the middle voltage range of the input signal.