nrf52840 timer current

[Nicolas Brunner]

Hello,

I have measured the current consumption of the timer example of SDK13.0.0 with PCA10056. With timer prescaler set at 16MHz i have 1.28 mA With timer prescaler set at 1MHz i have 1.27 mA This make a difference of 10uA but the datasheet say the difference should be of 65uA (5 vs 70 uA). Does someone know why is there a so big difference ? Are the current on the datasheet reliable ? If not, can we know what should be the expected current ?

[Stian Røed Hafskjold]

I did measurements with the timer example in SDK 13.0.0 on the PCA10056, out of the box, not changing anything. These are the results:

Frequency set to 16MHz: 543 µA
Frequency set to 1MHz: 398 µA

So the difference should be about 145 µA. I'm not sure why you get 1.28mA in total for just the timer example, but this is too high. Please see the PCA10056 user guide on how to measure current on the DK.

[Nicolas Brunner]

I have made the measure again following the guide with a 3V external supply:

• 1MHz: 423 uA
• 16MHz: 568 uA

with HFXO:

• 1MHz: 630 uA
• 16MHz: 776 uA

I also have a ~145 uA difference. It would be great to have correct value in the datasheet.

[Stian Røed Hafskjold]

Yes, I agree. The datasheet only looks at the current consumption of the peripheral itself. When the 16MHz clock is enabled, there are other parts of the digital domain that also consume more power. This is unfortunately not documented that well.