is limited to an approximate voltage range from 1.7V to 5.1V. Additional output voltage limits are configured in the
debugger firmware to ensure that the output voltage never exceeds the hardware limits of the AVR128DB48
microcontroller. The voltage limits configured in the on-board debugger on AVR128DB48 Curiosity Nano are 1.8–
5.5V.
Info:
The target voltage is set to 3.3V when the board is manufactured. It can be changed through
MPLAB
®
X IDE project properties and in the Atmel Studio 7 device programming dialog. Any change to
the target voltage is persistent, even after a power toggle. The resolution is less than 5 mV but may be
limited to 10 mV by the adjustment program.
Info:
Voltage settings that are set up in MPLAB
®
X IDE are not immediately applied to the board. The
new voltage setting is applied to the board when the debugger is accessed in any way, like pushing the
Refresh Debug Tool Status button in the project dashboard tab, or programming/reading program memory.
Info:
There is a simple option to adjust the target voltage with a drag-and-drop command text file to the
board. This supports a set of common target voltages. See section
details.
The MIC5353 supports a maximum current load of 500 mA. It is an LDO regulator in a small package, placed on a
small printed circuit board (PCB), and the thermal shutdown condition can be reached at lower loads than 500 mA.
The maximum current load depends on the input voltage, the selected output voltage, and the ambient temperature.
The figure below shows the safe operating area for the regulator, with an input voltage of 5.1V and an ambient
temperature of 23
°
C.
Figure 4-5. Target Regulator Safe Operation Area
The voltage output of the target regulator is continuously monitored (measured) by the on-board debugger. If it is
more than 100 mV over/under the voltage setting value, an error condition will be flagged, and the target voltage
regulator will be turned off. This will detect and handle any short-circuit conditions. It will also detect and handle if an
external voltage, which causes VCC_TARGET to move outside of the voltage setting monitoring window of ±100 mV,
is suddenly applied to the VTG pin, without setting the VOFF pin low.
AVR128DB48 Curiosity Nano
Curiosity Nano
©
2020 Microchip Technology Inc.
User Guide
DS50003037A-page 16
