Atmel Xplained Evaluation Board AT32UC3L0-XPLD AT32UC3L0-XPLD Data Sheet

32099G–06/2011

The AT32UC3L has several types of power supply pins:

•VDDIO: Powers I/O lines. Voltage is 1.8 to 3.3V nominal.

•VDDIN: Powers I/O lines and the internal regulator. Voltage is 1.8 to 3.3V nominal.

•VDDANA: Powers the ADC. Voltage is 1.8V nominal.

•VDDCORE: Powers the core, memories, and peripherals. Voltage is 1.8V nominal.

The ground pins GND are common to VDDCORE, VDDIO, and VDDIN. The ground pin for
VDDANA is GNDANA.

When VDDCORE is not connected to VDDIN, the VDDIN voltage must be higher than 1.98V.

Refer to 

 for power consumption on the various supply pins.

For decoupling recommendations for the different power supplies, please refer to the schematic
checklist.

The AT32UC3L embeds a voltage regulator that converts from 3.3V nominal to 1.8V with a load
of up to 60mA. The regulator supplies the output voltage on VDDCORE. The regulator may only
be used to drive internal circuitry in the device. VDDCORE should be externally connected to the
1.8V domains. See 

 for regulator connection figures.

Adequate output supply decoupling is mandatory for VDDCORE to reduce ripple and avoid
oscillations. The best way to achieve this is to use two capacitors in parallell between
VDDCORE and GND as close to the chip as possible. Please refer to 

for decoupling capacitors values and regulator characteristics.

Supply Decoupling

The AT32UC3L supports three power supply configurations:

• 3.3V single supply mode 

• 1.8V single supply mode

• 3.3V supply mode, with 1.8V regulated I/O lines

3.3V

1.8V

1.8V

Regulator