I've done some measurements on the KL25Z Freedom board and found that the MCU current doesn't drop with the supply voltage the way I would expect. Does the MCU use an internal voltage regulator or some other mechanism before powering its logic?
I power the board's P3V3 power rail directly with a variable power supply. I've cut the shorting trace on the back of J20, allowing diode D12 to isolate the linear voltage regulator U1. I measure the KL25Z MCU supply current by reading the voltage across J4 (with shorting resistor R73 removed) and dividing by 10 ohms. Here are my measurements.
|Voltage on P3V3||KL25Z Current|
|3.3 V||10.88 mA|
Thanks for any help!