PKK2 measurement difference between ampere mode & source mode

[Post1]

Hello,

 

I use a PKK2 for power measurements on a nRF9160DK and Feather nRF9160 from circuit dojo. With the UDP example to test it out the sleep current so I can determine if a battery powered device is possible.

 

When using the DK as in the example: https://www.youtube.com/watch?v=B42lPvkUSoc

I get the power consumption of <4uA in sleep mode. But when I use the PKK2 to power the board with source meter on the external supply pins I get a current of around 7mA. I also tried to power the DK with Ampere meter mode and external power supply with the same 7mA result. This is also the same with the feather. I would expect the nRF current measurement pins on the DK to give the same result with Ampere mode as the source meter mode on the external supply pins. But the difference is 1000* lager.

 

What is the reason for this big difference? Or what should I check / change?

[Øyvind]

Hello, 

Could you please provide pictures showing how you have connected the board?

Source meter -  the Device Under Test (DUT) is supplied power by the PPK2.

Ampere meter - the Device Under Test (DUT) must be supplied power from an external source (for example, Universal Serial Bus (USB)).

What setup are you using? 

Kind regards,
Øyvind

[Post1]

The second Ampere meter setup did I use with the <4uA result.

The other 2 setups looks like the 2 pics below with both the 7mA.

For the feather I don't have a separate pin to measure the amperage.

[Achim Kraus]

You measure the "complete DK (including the jlink + USB)" instead of only the nRF9160 via P22/VDD nRF.

And also in the case of the feather, you power the USB. See PPK2 with feather . If you use a feather before v6, please obey Quiescent current seems to depend on VBAT (v5) .