Methods and circuits for performing high-speed, high-resolution signal comparisons using offset cancellation, reduction of charge injection noise, and sharing of coupling capacitors between circuit stages. A multistage comparator circuit includes first and second preamplifiers electrically coupled to each other through series connections including coupling capacitors. A latch for storing the comparison output signal is electrically coupled to the output of the second preamplifier. The multistage comparator operates such that the offset voltages of the first preamplifier and of the second preamplifier and latch are stored on the coupling capacitors before performing comparisons.