Decoupling

[millicent bystander]

I'm designing around part 1490-1071-2-ND (nRF52840-QIAA)

Your ref designs show DEC5 decoupled with C9, 820pfF and states "not required for Fxx & later"

Do I need to place a component here?

[JONATHAN LL]

Hi,

The "not required for Fxx & later" refers to the fact that in the newer revisions(build code) of the SoC the external decupling of DEC5 is not needed. So the 820pF is not longer necessary and can be excluded. However it does not do any harm to have it there either. 

But if the SoC does not have a build code Fxx or later then C9@820pF it is need. 


If you don't know then include the DEC5 decupling capacitor in the layout and if at any later stage you find out it is not needed then you can remove it from the BOM and leave it NC/DNF.

Regards,
Jonathan