nPM1300 efficiency

My eval setup is PPK2(source mode) -> nPM1300EV - -> nRF54L15DK. I have my load connected to BUCK2, everything else is disabled.

I'm getting higher than expected input current consumption as measured by the PPK2.

Because nRFDK is a complex load, for the purpose of measurement I connected a 22K Ohm resistor to the output of nPM1300EV which should draw slightly more than the average amount of current as my nRF board. So PK2(source mode) -> nPM1300EV - -> 22K load.

My measurements are thus:

Input voltage 3.6v

Input average current 60uA

Output voltage 1.8v

Load current 81uA

This gives an overall efficiency of 69% which is low. How much can this be improved?

Also, I notice that when I disconnect the load completely there is a quiescent draw of ~8uA, comprised of high (2mA) spikes every 1 second. I assume this is the EV board's host CPU polling the nPM1300?

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