External clock source for feeding RTC (low power mode)

[WojciechS]

Hello All,

Regarding specification of nRF82540, we can use external clock source to feed LFCLK->RTC. (low swing clock or rail to rail clock signal)

Are there any contraindications to use external clock signal in low power mode?

Probably, if we use the existing clock signal (available in our system) to feed the nRF RTC we can improve overall power consumption.

Thank you.

[ovrebekk]

Hi Sobieraj

Using an external clock should work fine in low power mode, yes. 

It shouldn't be a large difference, but you save around 0.3uA or so by not having to run the internal LFRC oscillator. 

Also, if the external clock source is more accurate than the internal RC (which I assume it is) you might be able to reduce the power consumption of the wireless stack a little. 

Best regards
Torbjørn