8.2.2 System Power-Down

The following figure shows the SAM9X75 SOM Series power-down sequence that starts by asserting the SHDN line to "0".

Once SHDN and NRST are asserted, the supply inputs can be immediately shut down without any specific timing or order. VDDBU may not be shut down if the application uses a backup storage element on this supply input.

Figure 8-3. Recommended Power-Down Sequence

Note:

SHDN is generated internally by a software request from the SAM9X75 SiP device.
All these signals and power rails are controlled internally by the MCP16502 PMIC and are switched off at the same time.
This group is supplied externally and requires no specific order. Only timing t₈ must be respected.

Table 8-3. Power-Down Timing Requirements
Symbol	Parameter	Conditions	Min	Typ	Max	Unit
t₆	SHDN to NRST delay at power-down	Delay from asserted SHDN to NRST generation	0	–	10	µs
t₇	NRST delay at power-down	Delay from asserted NRST to first supply turn-off	0	–	10	µs
t₈	External supply delay at power-down	Delay from asserted NRST to external supplies turn-off	t₇	–	1	ms