5.1 Power Domains

Figure 5-1. Power Domain Overview

Note: For the AVR® DBFamily of devices, AVDD is internally connected to VDD (not separate power domains).

The AVR® DB family of devices has several power domains with the following power supply pins:


Domain	Pin	Description
V_DD	VDD	Powers I/O lines, XOSCHF and the internal voltage regulator
V_DD	AVDD	Powers I/O lines, XOSC32K (external 32.768 kHz oscillator), and the analog peripherals
V_DDIO2	VDDIO2	Powers I/O lines, optionally at a different voltage from V_DD

The same voltage must be applied to all VDD and AVDD pins. This common voltage is referred to as V_DD in the data sheet.

The ground pins, GND, are common to VDD, AVDD and VDDIO2.

A subset of the device I/O pins can be powered by V_DDIO2. This power domain is independent of V_DD. Refer to the Multi-Voltage I/O section for further information.

For recommendations on layout and decoupling, refer to the Hardware Guidelines section.