power consumption of around 0.77mA even after system off command

[Juliusc]

I noticed that my custom pcb draws power even when just commanding a simple system off call..

Im certain that this is not hardware related as I did the same with one of the nrf examples from SDK 15.3 and the power consumption goes down to below 100uA which I would expect. 

Which preprocessor definitions or project configurations could lead to such behavior?

My main loop is just 

NRF_POWER->SYSTEMOFF = 1; 

nothing else so it must be in the configuration but I cant point out where. How would I find a source for this problem?

Im using an nrf52840 uC on a custom board but as I said hardware shouldn't be a problem as I tested this. 

[Susheel Nuguru]

Tested this on our DK and it seems to give proper sleep currents of average 4uA

[Juliusc]

Okay so I found out that one gpio channel pulled current if i didn't explicitly clear it

now I got 400uA left, what should I check next regarding power consumption? I already read through this thread:  How to minimize current consumption for BLE application on nRF51822
and also went through all the other guides that describe something in this direction - but those 400uA don't go away.

Any idea on this? 

[Susheel Nuguru]

Sorry for late response Jullus, we were away on Easter holidays in Norway. Thanks for your patience in waiting.

400uA sounds like the HFCLK is kept active, which could happen when the peripheral needing HFCLK is still on. Do you have full control on which peripherals are enabled?

Im certain that this is not hardware related as I did the same with one of the nrf examples from SDK 15.3 and the power consumption goes down to below 100uA which I would expect. 

What example did you test that worked with the power consumption ? Have you taken that example as template and removed everything else from the main() function with just SYSTEMOFF = 1?

Can you share your code?