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 kit target section by manipulating the MIC5353’s feedback voltage. The hardware implementation 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 PIC18F47K42 microcontroller. The voltage limits configured in the on-board debugger on PIC18F47K42 Curiosity Nano are 2.3-5.1V.

Info: The target voltage is set to 3.3V in production. It can be changed through MPLAB X IDE project properties. Any change to the target voltage is persistent, even through a power toggle.

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 3-3. Target Regulator Safe Operation Area