NRF52840 too high systemOFF current

[jonas.woerner]

Hi,

I am trying to get my systemOFF current below 1uA, but Im struggeling.

normally I use MBED, but to eliminate that variable, I just did a test without MBED, I took the nordic blinky example(SDK15.0) and added

sd_power_system_off();

to the

BLE_GAP_EVT_DISCONNECTED

so, when I connect and disconnect, the current drops from about 1mA to 36uA. This is exactly the same behaviour as I see on my application running with MBED.

So, its not MBEDs fault, so it must be mine.

what am I missing out?! I have searched through all of the posts about the systemOFF mode drawing too much current, but none of these problems were like mine.

Is it possible, that its because I am using an preview-DK? I have read all the errata about the first revision of the NRF, and didnt find something similiar to my problem.

thanks,

Jonas

[Simonr]

Hi Jonas

What are you using to measure the current? If you are measuring over the current measurement header and powering the board with USB, my guess is that this extra current is USB interference.

Best regards,

Simon

[jonas.woerner]

Hi,

yes, I am measuring with the PPK and USB as power supply, but that cannot be the isssue, as I am able to get the current down below 1uA, by creating an empty program with just NRF_POWER->SYSTEMOFF = 1 in the main function.

are you able to reproduce my issue created with the blinky example? maybe on a preview DK vs release DK?

anyways, I will order a new DK and continue testing with it.

thanks.