Current consumption addtion with 32.768 kHz synthesized from HFCLK

[Yaniv Reibenbach]

Hello,

I read in your datasheet the follwoing:

"32.768 kHz synthesized from HFCLK (LFSYNT)

LFCLK can also be synthesized from the HFCLK clock source. The accuracy of LFCLK will then be the accuracy of the HFCLK.

Using the LFSYNT clock avoids the requirement for a 32.768 kHz crystal, but increases average power consumption as the HFCLK will need to be requested in the system."

How much do you estimate the addtional currents using this configuration in 1 sec advertize ?

Regards,

Yaniv

[AmbystomaLabs]

Pretty straightforward, the LF synth runs the HF ext all the time.  HF_EXT is listed as 250uA for nRF52832.

If you don't have an LF crystal then better to use LF_RC.  When running the SD the LF_RC is kept to 250ppm by periodically calibrating against the HF_EXT.  In this manner the HF_EXT is only run for milliseconds every few seconds. 

You can search in the devzone for the precise current consumption from using the LF_RC.  But offhand I think including the cal it is around 2.5uA.