Power Domains

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

The same voltage must be applied to all VDD and AVDD pins. This common voltage is referred to as VDD 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 VDDIO2. This power domain is independent of VDD. Refer to the Multi-Voltage I/O section for further information.

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