SAM3S_14 Datasheet, PDF (18/1087 Pages) ATMEL Corporation – AT91SAM ARM-based Flash MCU

5. Power Considerations
5.1 Power Supplies
The SAM3S product has several types of power supply pins:
z VDDCORE pins: Power the core, the embedded memories and the peripherals; voltage ranges from 1.62V to
1.95V.
z VDDIO pins: Power the Peripherals I/O lines (Input/Output Buffers); USB transceiver; Backup part, 32 kHz crystal
oscillator and oscillator pads; ranges from 1.62V to 3.6V
z VDDIN pin: Voltage Regulator Input, ADC, DAC and Analog Comparator Power Supply; Voltage ranges from 1.8V
to 3.6V
z VDDPLL pin: Powers the PLLA, PLLB, the Fast RC and the 3 to 20 MHz oscillator; voltage ranges from 1.62V to
1.95V.
5.2 Voltage Regulator
The SAM3S embeds a voltage regulator that is managed by the Supply Controller.
This internal regulator is intended to supply the internal core of SAM3S. It features two different operating modes:
z In Normal mode, the voltage regulator consumes less than 700 μA static current and draws 80 mA of output
current. Internal adaptive biasing adjusts the regulator quiescent current depending on the required load current.
In Wait Mode quiescent current is only 7 μA.
• In Backup mode, the voltage regulator consumes less than 1 μA while its output (VDDOUT) is driven internally to GND.
The default output voltage is 1.80V and the start-up time to reach Normal mode is inferior to 100 μs.
For adequate input and output power supply decoupling/bypassing, refer to the “Voltage Regulator” section in the
“Electrical Characteristics” section of the datasheet.
5.3 Typical Powering Schematics
The SAM3S supports a 1.62V-3.6V single supply mode. The internal regulator input connected to the source and its
output feeds VDDCORE. Figure 5-1 shows the power schematics.
As VDDIN powers the voltage regulator, the ADC/DAC and the analog comparator, when the user does not want to use
the embedded voltage regulator, it can be disabled by software via the SUPC (note that it is different from Backup mode).
Figure 5-1. Single Supply
Main Supply
(1.8V-3.6V)
VDDIO
VDDIN
VDDOUT
VDDCORE
USB
Transceivers.
ADC, DAC
Analog Comp.
Voltage
Regulator
VDDPLL
Note:
For USB, VDDIO needs to be greater than 3.0V.
For ADC, VDDIN needs to be greater than 2.0V.
For DAC, VDDIN needs to be greater than 2.4V.
SAM3S [DATASHEET] 18
6500E–ATARM–11-Feb-13