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KL25Z Supply Current Relationship with VDD

Question asked by Alex Dean on Jul 23, 2013
Latest reply on Jul 25, 2013 by Alex Dean

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 P3V3KL25Z Current
3.3 V10.88 mA
3.010.71
2.710.71
2.410.58
2.010.43

Thanks for any help!

 

Regards,

Alex

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