Maximum run current of the watchdog

[Remo]

Hi

I'm using the watchdog of the nRF52832 Rev. 1.

The PS V1.4 states that the maximum run current of the watchdog is 2uA while the typical current is only 0.3uA. Can you say under what conditions the maximum current applies? I'm asking this because the watchdog is also running when the CPU is sleeping and I would like to know if the 2uA also could be consumed in this state (this would almost double the current consumption in the System ON low power mode).

Many thanks in advance.

Best regards

Remo

[Jared]

Hi,

The maximum current specified in the specification is due to chip variation and is only for the watchdog peripheral. I used the power profiler kit and measured a total of 2.5 µA sleep current with RAM retention and the watchdog running. The sleep current with RAM retention is specified as typical 1.5 µA which means that the watchdog peripheral is using around 1 µA during sleep.

regards

Jared 

[Remo]

Hi Jared

Thank you for your answer.

Just for clarification, isn't the current of the LFRC or LFXO included in the remaining 1uA as well?

Another question, does the watchdog consume the current also when it is configured to halt while the CPU is sleeping? I'm asking this because my measurements didn't show a difference between a running and a halted watchdog.

Best regards

Remo

[Jared]

Hi,

Remo said:

Just for clarification, isn't the current of the LFRC or LFXO included in the remaining 1uA as well?

 Yes, so the actual current of the peripheral will be less than 1 µA.

Remo said:

Another question, does the watchdog consume the current also when it is configured to halt while the CPU is sleeping? I'm asking this because my measurements didn't show a difference between a running and a halted watchdog.

Almost the same, if the WDT is not configured to run then it would release the LFCLK and consume only ~0.1  µA to maintain its state.

Jared

[Remo]

Thank you very much. It helped a lot!