...........continued
Debugger Signal
Target MCU
Description
VBUS
—
VBUS voltage for external use
VOFF
—
Voltage Off input. Disables the target regulator and
target voltage when pulled low.
VTG
—
Target voltage
GND
—
Common ground
Figure 3-3. Curiosity Nano Standard Pinout
USB
DEBUGGER
PS LED
NC
ID
CDC RX
CDC TX
DBG1
DBG2
VBUS
VOFF
DBG3
DBG0
GND
VTG
CURIOSITY NANO
3.3
Power Supply
The board is powered through either of the USB ports and contains two LDO regulators, one to generate 3.3V for
the on-board debugger and an adjustable LDO regulator for the target PIC24FJ64GU205 microcontroller and its
peripherals. The voltage from a USB connector can vary between 4.4V to 5.25V (according to the USB specification)
and will limit the maximum voltage to the target. The figure below shows the entire power supply system on
PIC24FJ64GU205 Curiosity Nano.
Figure 3-4. Power Supply Block Diagram
Debugger
USB
Target
MCU
Power source
Cut strap
Power consumer
P3V3
Debugger
Power converter
Debugger
Regulator
VUSB
Target
Regulator
Power
Supply
strap
Adjust
Level
shifter
VLVL
VREG
I/O
I/O
GPIO
straps
I/O
On/Off
Measure
On/Off
PTC
Fuse
Power protection
Target
Power
strap
VTG
VBUS
#VOFF
ID system
Target
USB
Power
MUX
Curiosity Nano
©
2021 Microchip Technology Inc.
User Guide
50003124A-page 14
