VDDIO and VDDIN must rise simultaneously, prior to VDDCORE, VDDPLL and VDDUTMIC rising. This is respected if VDDCORE, VDDPLL and VDDUTMIC are supplied by the embedded voltage regulator.
If VDDCORE is powered by an external voltage regulator, VDDIO and VDDIN must reach their minimum operating voltage before VDDCORE has reached VDDCOREmin. The minimum slope for VDDCORE is defined by:
If VDDCORE rises at the same time as VDDIO and VDDIN, the minimum and maximum rising slopes of VDDIO and VDDIN must be respected. Refer to the section “DC Characteristics”.
In order to prevent any overcurrent at powerup, it is required that VREFP rises simultaneously with VDDIO and VDDIN.
Figure 1. Powerup Sequence
