6.1 Power Supply Configuration #1

The SAMA5D27 SOM1 is supplied by only one main supply.

In this configuration mode, all supplies are connected together and supplied by the main 3.3V supply. All PIOs have VDDIN_3V3 Power Rail as voltage reference.

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

Figure 6-2. Power-On Sequence Timing Diagram

Figure 6-3. Power-Off Sequence Timing Diagram

Table 6-1. Timing Values
Symbol	Description	Min.	Typ.	Max.	Unit
t_main⁽¹⁾	Main 3.3V Start-up Time	–	–	1	ms
t_start	Internal Delay before starting System Core Supplies	1	–	3	ms
t_por	Power-on Reset Delay	–	10	11	ms
t_soft	Software Shutdown Time	Depending on system off time			ms
t_{main_off}	Main 3.3V Power-off Time	–	–	1	ms
t_stop	Internal Delay before switching off System Core Supplies	1	–	3	ms

Note:

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 800µs. VDDBU must be applied at the same time as VDDIN_3V3 or just before. It is forbidden to apply VDDBU after VDDIN_3V3.