6.2 Power Supply Configuration #2

The SAMA5D27 SOM1 is supplied by different power supplies.

  • Backup domain is connected to a coin-cell supply.
  • The rest of the power inputs are connected to the main 3.3V supply.
In this configuration, the following PIOs have VDDBU Power Rail as reference. All other PIO have VDDIN_3V3 Power Rail as reference.
  • COMPP and COMPN
  • PIOBU1 to PIOBU7
  • RXD, SHDN and WKUP
Figure 6-4. Power Configuration #2

In this configuration, the two following timing sequences are applied.

Figure 6-5. Power-On Sequence Timing Diagram
Figure 6-6. Power-Off Sequence Timing Diagram
Table 6-2. Timing Values
SymbolDescriptionMin.Typ.Max.Unit
tmain(1)Main 3.3V Start-up Time––1ms
tstartInternal Delay before starting System Core Supplies1–3ms
tporPower-on Reset Delay–1011ms
tsoftSoftware Shutdown TimeDepending on system off timems
tmain_offMain 3.3V Power-off Time––1ms
tstopInternal Delay before switching-off System Core Supplies1–3ms
Note:
  1. The three supplies VDDIN_3V3, VDDISC and VDDSDHC must be applied at the same time. If a delay is implemented, it must be lower than tstart.