ATSAM3U datasheet(15/62 Pages) ATMEL

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6430CS–ATARM–09-Apr-10

SAM3U Series

Power Considerations

5.1

Power Supplies

The SAM3U product has several types of power supply pins:

• VDDCORE pins: Power the core, the embedded memories and the peripherals; voltage

ranges from 1.62V to 1.95V.

• VDDIO pins: Power the Peripherals I/O lines; voltage ranges from 1.62V to 3.6V.

• VDDIN pin: Powers the Voltage regulator

• VDDOUT pin: It is the output of the voltage regulator.

• VDDBU pin: Powers the Slow Clock oscillator and a part of the System Controller; voltage

ranges from 1.62V to 3.6V. VDDBU must be supplied before or at the same time than VDDIO

and VDDCORE.

• VDDPLL pin: Powers the PLL A, UPLL and 3-20 MHz Oscillator; voltage ranges from 1.62V

to 1.95V.

• VDDUTMI pin: Powers the UTMI+ interface; voltage ranges from 3.0V to 3.6V, 3.3V nominal.

• VDDANA pin: Powers the ADC cells; voltage ranges from 2.0V to 3.6V.

Ground pins GND are common to VDDCORE and VDDIO pins power supplies.

Separated ground pins are provided for VDDBU, VDDPLL, VDDUTMI and VDDANA. These

ground pins are respectively GNDBU, GNDPLL, GNDUTMI and GNDANA.

5.2

Voltage Regulator

The SAM3U embeds a voltage regulator that is managed by the Supply Controller.

This internal regulator is intended to supply the internal core of SAM3U but can be used to sup-

ply other parts in the application. It features two different operating modes:

• In Normal mode, the voltage regulator consumes less than 700 µA static current and draws

150 mA of output current. Internal adaptive biasing adjusts the regulator quiescent current

depending on the required load current. In Wait Mode or when the output current is low,

quiescent current is only 7µA.

• In Shutdown mode, the voltage regulator consumes less than 1 µA while its output is driven

internally to GND. The default output voltage is 1.80V and the start-up time to reach Normal

mode is inferior to 400 µs.

For adequate input and output power supply decoupling/bypassing, refer to “Voltage Regulator”

in the “Electrical Characteristics” section of the product datasheet.

5.3

Typical Powering Schematics

The SAM3U supports a 1.8V-3.6V single supply mode. The internal regulator input connected to

the source and its output feed VDDCORE. Figure 5-1, Figure 5-2, Figure 5-3 show the power

schematics.

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