Custom nRF52832 board doesn't radiate

[Hossein Kasaei]

Hi,

I've developed a custom board with nrf52832 based on Nordic reference layout. The problem is that when I upload a BLE code, it doesn't appear in nRF Connect app. I tested the code on nRF52 DK and it worked well so this is an hardware issue, but I think RF front end is not the problem because it doesn't appear in nRF Connect at all even in a very close range. I'm using nRF Connect SDK. Blinky example works perfectly on this board.

Designed board :

SoC section schamtic :

Thank you in advance

[Frank Viganske]

Hi,

the C13 footprint looks quite large for a 0.8pF capacitor. Are you sure you have used the right value here? I'd expect C13 to be have the same footprint size as C14.

Best regards

Frank

[Hossein Kasaei]

Hi,

C13 has 0805 footprint which is not the most suitable option for the RF front end, but it is selected based on available components. 0.8pF capacitor with 0805 package is not wired, but your answer suspect me about the value of capacitor I bought, so I checked it with capacitance meter and found out that it is 4.7uF cap which is the supplier mistake. I'm going to change the capacitor and will announce about the result.

[Kaja]

Hi, 

here you have done a couple of design mistakes on the RF part of the design:
1. There should not be any routing under the RF path. 
2. The grounding of C13 should be done via the VSS pin 31. 
3. There should not be any routing under the 32 MHz crystal. 

There are more things to improve, but first: 

Can you upload the datasheet for the two crystals you are using? Both for the 32 kHz and the 32 MHz. 


Best regards,
Kaja

[Hossein Kasaei]

I changed the capacitor but the problem is still there.

[Hossein Kasaei]

Hi,

Thanks for your tips I'll consider them for next designs.

datasheets :

nsk_crystal.pdf
CM415 datasheet.pdf