Changing stack-up layers in designing nRF52832 with CSP package

[Dave]

Hi guys,

I have a question when design the pcb layout stack with nRF52832, CSP package (CHAA). As recommendation from Nordic, using 4 layers will give best performance but is it ok if I change to use just 2 layers intead of 4 layers?

Here is my configuration: Top layer : 12um

Dielectric : 50um, FR4, e = 4.8

Bottom layer : 12um

To maintain the 50ohm impedance of RF signals, I changed the width of the feed line to 3mils (instead of using 8 mils in 4 layers configuration).

Is it ok to keep the performance of RF signal still good as 4 layers? And with the thickness of the dielectric is so small, is it effect on any working principle of nRF52832?

Many thanks