8.
Power Supply and Start-Up Considerations
8.1.
Power Domain Overview
VOLTAGE
REGULATOR
VDDIO
VDDCORE
GND
ADC
AC
LCD
PTC
V
D
D
A
N
A
G
N
D
A
N
A
PA[7:2]
PB[9:4]
PA[1:0]
BOD33
POR
BOD12
V
B
A
T
(P
B
[3
])
XOSC32K
OSCULP32K
PB[3:0]
OSC16M
VDDOUT
PB[31:1
1]
P
A
[3
1:8
]
VDDIO
VBAT
VSWOUT
RTC, PM,
SUPC, RSTC
VOLTAGE
REGULATOR
VDDBU
VDDANA
DFLL48M
FDPLL96M
Digital Logic
CPU, Peripherals
VDDCORE
XOSC
PC[1:0]
PC[7:5]
PC[3:2]
PC[28:8]
VLCD
The Atmel SAM L22 power domains are not independent of each other:
•
VDDCORE and VDDIO share GND, whereas VDDANA refers to GNDANA.
•
VDDCORE serves as the internal voltage regulator output.
•
VSWOUT and VDDBU are internal power domains.
8.2.
Power Supply Considerations
8.2.1.
Power Supplies
The Atmel SAM L22 has several different power supply pins:
•
VDDIO powers I/O lines and OSC16M, XOSC, the internal regulator for VDDCORE and the
Automatic Power Switch. Voltage is 1.62V to 3.63V
•
VDDANA powers I/O lines and the ADC, AC, LCD, and PTC. Voltage is 1.62V to 3.63V
•
VLCD has two alternative functions:
–
Output of the LCD voltage pump when VLCD is generated internally. Output voltage is 2.5V to
3.5V.
–
Supply input for the bias generator when VLCD is provided externally by the application. Input
voltage is 2.4 to 3.6V.
•
VBAT powers the Automatic Power Switch. Voltage is 1.62V to 3.63V
•
VDDCORE serves as the internal voltage regulator output. It powers the core, memories,
peripherals, DFLL48M and FDPLL96M. Voltage is 0.9V to 1.2V typical.
•
The Automatic Power Switch is a configurable switch that selects between VDDIO and VBAT as
supply for the internal output VSWOUT, see the figure in
Atmel SAM L22G / L22J / L22N [DATASHEET]
Atmel-42402E-SAM L22G / L22J / L22N_Datasheet_Complete-07/2016
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