
47
32117DS–AVR-01/12
AT32UC3C
The 3.3V regulator is connected to the 5V source (VDDIN_5 pin) and its output feeds the USB
pads. If the USB is not used, the 3.3V regulator can be disabled through the VREG33CTL field
of the VREGCTRL SCIF register.
I/O lines and analog blocks will be powered by the same power (VDDIN_5 = VDDIO1 = VDDIO2
= VDDIO3 = VDDANA).
Figure 6-1.
5V Single Power Supply mode
6.1.3.2
3.3V Single Supply Mode
In 3.3V single supply mode, the VDDIN_5 and VDDIN_33 pins should be connected together
externally. The 1.8V internal regulator is connected to the 3.3 V source (VDDIN_5 pin) and its
output feeds VDDCORE.
The 3.3V regulator should be disabled once the circuit is running through the VREG33CTL field
of the VREGCTRL SCIF register.
I/O lines and analog blocks will be powered by the same power (VDDIN_5 = VDDIN_33 =
VDDIO1 = VDDIO2 = VDDIO3 = VDDANA).
VDDIO1
VDDIO2
VDDIO3
CPU
Peripherals
Memories
SCIF, BOD,
RCSYS
3.3V
Reg
+
-
Analog: ADC, AC, DAC, ...
VDDIN_5
VDDANA
GNDANA
VDDCORE
COUT2
COUT1
GNDCORE
GNDPLL
PLL
GNDIO1
GNDIO2
GNDIO3
BOD50
BOD18
BOD33
1.8V
Reg
POR
CIN2
CIN1
VDDIN_33
COUT2
COUT1
4.5-
5.5V