...........continued
Debugger Signal
Target MCU
Description
V
BUS
—
V
BUS
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 the USB port and contains two LDO regulators, one to generate 3.3V for the on-board
debugger and an adjustable LDO regulator for the target PIC16F15276 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 PIC16F15276 Curiosity
Nano.
Figure 3-4. Power Supply Block Diagram
USB
Target
MCU
Power source
Cut strap
Power consumer
P3V3
DEBUGGER
Power converter
DEBUGGER
Regulator
V
USB
Target
Regulator
Power
Supply
strap
Adjust
Level
shifter
VLVL
V
REG
I/O
I/O
GPIO
straps
I/O
On/Off
Measure
On/Off
ID system
#V
OFF
PTC
Fuse
Power protection
V
BUS
Target
Power
strap
VTG
3.3.1
Target Regulator
The target voltage regulator is a MIC5353 variable output LDO. The on-board debugger can adjust the voltage output
supplied to the board target section by manipulating the MIC5353’s feedback voltage. The hardware implementation
Curiosity Nano
©
2021 Microchip Technology Inc.
User Guide
DS50003143A-page 13
