nrf5340 Internal Capacitors CL for HFXO

[matt.heins]

I'm a little confused about how to determine the value to set in the registers for the internal capacitors. If I select 10pF, that means that there is an internal C1 and C2 which I use in the equation to get C1' and C2' to then calculate CL, correct? For instance, I am trying to get CL to be 6pF. Cpin is 2.5pF. Cpcb is 0.5pF. So, I select 9pF for the internal capacitors and get a CL of 6pF. Could you please verify? And perhaps an example in the datasheet would clear it up, or maybe a simple table?

[JONATHAN LL]

Hi,

The Crystal section can be a bit confusing I agree. There has been a previous ticket here, (+) nRF5340 LFXO Internal Load Cap Setting - Nordic Q&A - Nordic DevZone - Nordic DevZone (nordicsemi.com) , on the topic of the LF. I believe the same applies to the HF.

There is a section in the PS on using the internal caps. 
This is the equation given to select the internal values. 

CAPVALUE = (((FICR->XOSC32MTRIM.SLOPE+56)*(CAPACITANCE*2-14))
           +((FICR->XOSC32MTRIM.OFFSET-8)<<4)+32)>>6;

Regards,
Jonathan