Datasheet

43
32142D–06/2013
ATUC64/128/256L3/4U
6.1.3.3 3.3V Supply Mode with 1.8V Regulated I/O Lines
In this mode, the internal regulator is connected to the 3.3V source and its output is connected
to both VDDCORE and VDDIO as shown in Figure 6-4. This configuration is required in order to
use Shutdown mode.
Figure 6-4. 3.3V Supply Mode with 1.8V Regulated I/O Lines
In this mode, some I/O lines are powered by VDDIN while other I/O lines are powered by VDDIO.
Refer to Section on page 10 for description of power supply for each I/O line.
Refer to the Power Manager chapter for a description of what parts of the system are powered in
Shutdown mode.
Important note: As the regulator has a maximum output current of 60 mA, this mode can only be
used in applications where the maximum I/O current is known and compatible with the core and
peripheral power consumption. Typically, great care must be used to ensure that only a few I/O
lines are toggling at the same time and drive very small loads.
VDDIO
VDDCORE
+
-
1.98-3.6V
VDDANA
ADC
VDDIN
GND
GNDANA
CPU,
Peripherals,
Memories,
SCIF, BOD,
RCSYS,
DFLL, PLL
OSC32K,
RC32K,
POR33,
SM33
I/O Pins
I/O Pins
OSC32K_2,
AST, Wake,
Regulator
control
Linear
regulator