4.2.1 Power Architecture

Basic operation of the ATSAMA5D27-WLSOM1 requires a +5.0V input voltage supply and a VDDBU (+1.65V to +3.6V) input voltage supply, generally ensured by a backup battery. +5.0V power is supplied to the VDD_MAIN domain.

CAUTION: As a general design rule, it is recommended to connect all input supply pins, except VDDFUSE which must be connected to GND by a 100 Ohms resistor if not used, to your power supply and at least a matching number of ground (GND) pins. For the best EMI performance, it is recommended to connect ALL ground pins of the ATSAMA5D27-WLSOM1 module to a solid ground plane.

Power-on is controlled through the nSTART_SOM signal. This signal must be provided by the host board; for example, via an automated reset controller or a push-button.

The ATSAMA5D27-WLSOM1 module can operate from a single voltage supply (VDD_MAIN) with a value comprised between +3.0V and +5.5V and, with the MCP16502 PMIC device, internally generates the voltage supplies required by the SAMA5D2 processor and on-board components.

The PMIC on-board switching regulators generate the 3.3V, 1.20V, 1.25V and 1.8V voltage supplies required by the SAMA5D27 processor and on-board components.

The ATSAMA5D27-WLSOM1 delivers external power supplies to the main board application, such as VDD_DDR (1.8V with 900 mA current capability), VDD_3V3 (3.3V with 600mA output current capability) and VLDO2 output (1.8V to 3.3V with 300 mA output current capability).

Figure 4-4. ATSAMA5D27-WLSOM1 Power Architecture