Datasheet

12
6120F–ATARM–03-Oct-06
AT91SAM7X512/256/128 Preliminary
Adequate input supply decoupling is mandatory for VDDIN in order to improve startup stability
and reduce source voltage drop. The input decoupling capacitor should be placed close to the
chip. For example, two capacitors can be used in parallel: 100 nF NPO and 4.7 µF X7R.
5.4 Typical Powering Schematics
The AT91SAM7X512/256/128 supports a 3.3V single supply mode. The internal regulator input
connected to the 3.3V source and its output feeds VDDCORE and the VDDPLL. Figure 5-1
shows the power schematics to be used for USB bus-powered systems.
Figure 5-1. 3.3V System Single Power Supply Schematic
Power Source
ranges
from 4.5V (USB)
to 18V
3.3V
VDDIN
Voltage
Regulator
VDDOUT
VDDIO
DC/DC Converter
VDDCORE
VDDFLASH
VDDPLL