System level serial powering studies of RD53A chip

Serial powering is the baseline choice for low mass power distribution for the CMS and ATLAS HL-LHC pixel detectors. The RD53A prototype chip (65 nm CMOS) integrates 2 shunt-LDO (SLDO) regulators that allow providing constant voltage to each power domain (analog and digital) within a serial power chain with constant current. This paper presents a detailed analysis based on simulations and measurements of the RD53A chip behavior at system level. SLDO performance and system transient behavior (start-up, load changes, parasitic components implications).