hey guys, i finally assembled my nrf52840 pa board. it was sitting there for quite some time but i couldn't find some spare time to get on with it but here are some experiences i had.
i was worried about this aQFN footprint but it all went well, looks like everything is soldered correctly and i ordered my boards with cheapest HASL instead of ENIG.
then i uploaded the adafruit feather bootloader to test the bluetooth and it all works ok. i used my iphone 6s as a central device and im not sure if my phone has LNA or PA module inside for bluetooth so it may or may not be better if i use another module like the one i did. this connection is from my module to my phone WITHOUT PA activated at tx power max(8):
and this is after i activate PA chip on board :
and this is with 3 solid walls in between at around 10 meters distance
as you can see signal strength is massively different pa bumps up the signal from -87dbm to -30dbm which is probably day and night difference.
but with this setup you manually have to enable and disable rx and tx pins in order to keep the communication. well im not really good at coding but im going to try make the whole thing automatically because nordic already has this PA assist feature buried inside its BLE core, just gotta find a way to make it work.
final board, forgot to add i opted to use pcb antenna but i could switch to external antenna as well i just have to reposition the 0 ohm resistor to use that SMA on the side and then results could get even better: