Having trouble achieving the 0.4 uA system off sleep current listed on page 56 of the nrf52840 product spec

[willml]

I am using the nrf52840 DK.  Have the debug section of the board turned off.  I have the external flash removed from the circuit.  I am using a 3V external supply. I am using a Keysight 34465a to collect current data.  When running the ble_app_pwr_profiling example, I see this in system off mode:

If I compute the average current and zoom in on the lower part of the plot you get this:

Where the red line, at about 540 nA is the average including the DC/DC converter spikes.   Is there something else that needs to be turned off to get to 400 nA?  I realize this is a hard measurement to make, but the data I am getting is pretty repeatable, always in the 550 nA ballpark.  My application is a battery operated medical device and getting to 400 nA would make a difference in performance for me.

Thank you,

--bill

[Jared]

Hi Bill,

Thank you for a good description of your question.

Samples will have some variation of sleep current. The specified sleep current in the product specification is the expected value of this variation (average) .  A measured sleep current of 540 nA is within of what is acceptable, which means that this is the sleep current of your sample given that measurement setup is correct. 

best regards

Jared