SLUAAK2 November 2022 AM625
AM62x requires the different power rails to be ramped up in a certain sequence to ensure a reliable and fault free operation. Figure 1-2 shows the power-on sequence of the power rails. Shaded regions in Figure 1-2 indicate, that particular rail is allowed to ramp up at any time within this region. The 3V3, VDDSHVx and VDDSHV5 rails are the first rails to be powered on. Next, the 1.8V analog and digital rails are ramped up. This is followed by the 1.2 V DDR rail. By ramping up the 0.75 V, VDD_CORE before the 0.85 V, VDDR_CORE, it is made sure that the VDDR_CORE voltage never exceeds the VDD_CORE voltage by 180 mV. If VDD_CORE is operating at 0.85 V, both VDD_CORE and VDDR_CORE can be supplied by the same rail and there is no ramp up requirement between them. The 1.8 V, VPP is the eFuse programming supply, which shall be left floating (HiZ) or grounded during power-up/down sequences and during normal device operation. This supply shall only be sourced while programming.
For a detailed description of the power-on sequencing please refer to section 7.10.2.2.1 of the data sheet.