nRF54L15 ADC Rsource value

[Poki Huang]

Hi 

I want to check the nRF54L15 ADC Rsource value

As below pic., P1.07/AIN3 input voltage will be 0.6V (1.8V divider by R429 & R428)

So the Rsource value will be R429//R428 value(~666Kohm) or R429+R428 value(3Mohm)?

Thank you

Poki

[ketiljo]

As below pic., P1.07/AIN3 input voltage will be 0.6V (1.8V divider by R429 & R428)

Yes

So the Rsource value will be R429//R428 value(~666Kohm) or R429+R428 value(3Mohm)?

Take a look at this:  https://devzone.nordicsemi.com/nordic/nordic-blog/b/blog/posts/measuring-lithium-battery-voltage-with-nrf52 

When using large resistors in the voltage divider, you will load the divider when the ADC samples. You can use a buffer capasitor that will be charged to the divider level to avoid this.