5.3 Power Supplies

The SAMA5D27 SOM1 is supplied by an external 3.3V and generates its own internal supplies by interfacing with the Microchip MIC2800-G1JJYML Power Management Unit.

The MIC2800 is a high-performance power management IC, providing three output voltages with maximum efficiency and is optimized to respect the MPU power-up and power-down cycles.

Integrating a 2 MHz DC/DC converter with an LDO post regulator, the MIC2800 gives two high-efficiency outputs with a second, 300mA LDO for maximum flexibility. The DC-to-DC converter uses small values of L and C to reduce board space while still retaining efficiency over 90% at load currents up to 600mA.

The three outputs supply the following internal nodes:
  • DCDC set @ 1.8V supplies SAMA5D27C-D1G-CU DDR2 pads and device.
  • LDO1 set @ 1.25V supplies SAMA5D27C-D1G-CU Core.
  • LDO2 set @ 2.5V supplies SAMA5D27C-D1G-CU VDDFUSE pad.

The MIC2800 is a μCap design, operating with very small ceramic output capacitors and inductors for stability.

It is available in fixed output voltages in the 16-pin 3mm x 3mm MLF® lead-less package. For more information, refer to the product web page.

Figure 5-1. Power Management Unit Block Diagram
Note:
  1. The LOWQ# signal is connected to the PIOBU0 function of the SAMA5D27 device. This signal is internally pulled up at VDDBU level with a 100kΩ resistor.