6.3 Power Supply Configuration #3
Some power inputs of the SAMA5D27 SOM1 are grouped and others are supplied by a separated power supplies.
- Backup domain is connected to a coin cell.
- Camera sensor power input (VDDISC) is connected to a separate power supply set at one of the following voltage levels (1.8V/2.5V/2.8V/3.0V or 3.3V) depending on the camera sensor technology used in the application.
- The remaining power inputs are connected to the main 3.3V supply.
In this configuration, the following PIOs have:
- VDDBU Power Rail as reference
- COMPP and COMPN
- PIOBU1 to PIOBU7
- RXD, SHDN and WKUP
- VDDISC Power Rail as reference
- PC9 to PC25
- All other PIOs have VDDIN_3V3 Power Rail as reference.
In this configuration mode, the two following timing sequences are applied.
| Symbol | Description | Min. | Typ. | Max. | Unit |
|---|---|---|---|---|---|
| tmain(1) | Main 3.3V Start-up Time (From regulator available on the motherboard) | – | – | 1 | ms |
| ton1 | VDDISC Regulator Start-up Time (From regulator available on the motherboard) | – | – | 800 | µs |
| tstart | Internal Delay before starting System Core Supplies | 1 | – | 3 | ms |
| tpor | Power-on Reset Delay | – | 10 | 11 | ms |
| tsoft | Software Shutdown Time | Depending on system off time | ms | ||
| tmain_off | Main 3.3V Power-off Time (From regulator available on the motherboard) | – | – | 1 | ms |
| toff1 | VDDISC Regulator Power-off Time (From regulator available on the motherboard) | – | – | 1 | ms |
| tstop | Internal Delay before switching off System Core Supplies | 1 | – | 3 | ms |
Note:
- The supplies VDDIN_3V3 and VDDSDHC must be applied at the same time. If a delay is implemented, it must be lower than tstart.