SAM4L Datasheet, PDF (40/1185 Pages) ATMEL Corporation – ATSAM ARM-based Flash MCU

ATSAM4L4/L2
5.2 Power Supplies
The ATSAM4L4/L2 has several types of power supply pins:
• VDDIO: Powers I/O lines, the general purpose oscillator (OSC), the 80MHz integrated RC
oscillator (RC80M) . Voltage is 1.68V to 3.6V.
• VLCDIN: (ATSAM4LC only) Powers the LCD voltage pump. Voltage is 1.68V to 3.6V.
• VDDIN: Powers the internal voltage regulator. Voltage is 1.68V to 3.6V.
• VDDANA: Powers the ADC, the DAC, the Analog Comparators, the 32kHz oscillator
(OSC32K), the 32kHz integrated RC oscillator (RC32K)and the Brown-out detectors (BOD18
and BOD33). Voltage is 1.68V to 3.6V nominal.
• VDDCORE: Powers the core, memories, peripherals, the PLL, the DFLL, the 4MHz
integrated RC oscillator (RCFAST) and the 115kHz integrated RC oscillator (RCSYS).
– VDDOUT is the output voltage of the regulator and must be connected with or
without an inductor to VDDCORE.
The ground pins GND are common to VDDCORE, VDDIO, and VDDIN. The ground pin for
VDDANA is GNDANA.
For decoupling recommendations for the different power supplies, refer to the schematic
document.
5.2.1
Voltage Regulator
An embedded voltage regulator supplies all the digital logic in the Core and the Backup power
domains.
The regulator has two functionnal mode depending of BUCK/LDOn (PA02) pin value. When this
pin is low, the regulator is in linear mode and VDDOUT must be connected to VDDCORE exter-
nally. When this pin is high, it behaves as a switching regulator and an inductor must be placed
between VDDOUT and VDDCORE. The value of this pin is sampled during the power-up phase
when the Power On Reset 33 reaches V_POT+ (Section 42.8 ”Analog Characteristics” on page
1133)
Its output voltages in the Core domain (V_CORE) and in the Backup domain (V_BKUP) are always
equal except in Backup mode where the Core domain is not powered (V_CORE=0). The Backup
domain is always powered. The voltage regulator features three different modes:
• Normal mode: the regulator is configured as linear or switching regulator. It can support all
different Run and Sleep modes.
• Low Power (LP) mode: the regulator consumes little static current. It can be used in Wait
modes.
• Ultra Low Power (ULP) mode: the regulator consumes very little static current . It is dedicated
to Retention and Backup modes. In Backup mode, the regulator only supplies the backup
domain.
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