A: The phase-2 upgrade of the LHC will require novel pixel readout chips, which deliver hit information at drastically increased data rates and tolerate unprecedented radiation levels. The large-scale prototype chip RD53A has been designed by the RD53 collaboration and manufactured in a 65 nm CMOS process, suitable for the innermost layers of both the ATLAS and the CMS experiment. In order to verify the radiation hardness design goal of 500 Mrad total ionizing dose, RD53A has been irradiated using X-rays. The radiation effects on the performance of the data link, reset circuit and the clock generation have been investigated. Furthermore, the operating margins in terms of supply voltage and frequency have been analyzed.