3.3.1 Target Voltage Regulator

The voltage regulator for the target processor is a MIC5353 variable output LDO. The on-board debugger can adjust the voltage output that is supplied to the target section by manipulating the LDO's feedback voltage.

The hardware implementation is limited to an approximate voltage range of 1.7V-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 MCU.

The voltage limits configured in the on-board debugger for the Curiosity Nano+ Touch are 1.7V-3.6V. The target voltage is set to 3.3V in production and can be changed using MPLAB X IDE. Any change to the target voltage will be persistent between power cycles. The MIC5353 supports a maximum current load of 500 mA. It is an LDO regulator in a small package, placed on a small PCB, and the thermal shutdown condition can be reached at lower loads than 500 mA. The maximum current load depends on the input voltage, output voltage set point, and ambient temperature.

The following figure shows the safe operational area for the regulator given an input voltage of 5.1V and an ambient temperature of 23°C.