The present invention relates to a direct time-of-flight depth imaging sensor comprising: an array of photodetectors (43) arranged in one or more subgroups (41), wherein each subgroup (41) is divided into a plurality of minigroups (42) of photodetectors (43); digital processing and communication units (63) each associated to one of the minigroups (42), each comprising: a minigroup pixel address register (69) to store an address of the photodetector (43) in the respective minigroup (42) which has detected the last photon detection event within a coincidence window, wherein the coincidence window corresponds to detection window of a fixed duration starting with the first photon detection event within the respective subgroup (41); and a minigroup timestamp unit (68) configured to store minigroup timestamp data of the last photon detection event received in the coincidence window; a time to digital converter (61) configured to generate a subgroup timestamp data about the first photon detection event in the subgroup (41) during the coincidence window.