System OFF Current in 52840

RE: System OFF Current in 52840

Håkon Alseth — Thu, 31 May 2018 08:18:30 GMT

Hi,

Our tests are performed with the refresh mode spikes included.

The consumption between each refresh mode spike shall be 0, as the chip is not drawing any current at that point.

Best regards,

Håkon

RE: System OFF Current in 52840

michael a — Thu, 31 May 2018 02:58:38 GMT

Thank you for your answer.

But I think that the added average current is dominated by the refresh mode spikes, not by the PPK resolution nor the USB noise.

Is the refresh-spikes current taken into account in the current consumption numbers you report in the documentation (e.g. the system-OFF 0.4 uA)?

Best regards,

Michael

RE: System OFF Current in 52840

Håkon Alseth — Wed, 23 May 2018 12:01:23 GMT

Hi,

The spikes are due to the regulator refresh mode.

When using the PPK and measuring system off, you are entering the lower end of the resolution for the kit:

It measures current from 1 μA up to 70 mA and gives a detailed picture of the current profile for the user application.

Since you are measuring on a DK, then I suspect this added ~1 uA comes from leakage of external hardware on this board, as there are connections from the nRF to for instance the SEGGER IC, as explained in the note of the DK documentation. Powering the DK from USB will also provide a lot of noise when measuring current, so we recommend that you use a battery.

Kind regards,

Håkon