Embodiments of the present disclosure relate to various methods and example systems for carrying out analog-to-digital conversion of data acquired by arrays of nanogap sensors. The nanogap sensors described herein may operate as molecular sensors to help identify chemical species through electrical measurements using at least a pair of electrodes separated by a nanogap. In general, the methods and systems proposed herein rely on digitizing the signal as the signal is being integrated, and then integrating the digitized results. With such methods, the higher sample rate used in the digitizer reduces the charge per quantization and, therefore, the size of sampling capacitors used. Consequently, sampling capacitors may be made factors of magnitude smaller, requiring less valuable space on a chip compared to sampling capacitors used in conventional nanogap sensor arrays.