Matching network between NRF21540 and NRF52840 and the output antenna matching network of NRF21540

[Hiep Le]

Hi everyone, I am Hiep Le - a hardware design engineer

I am developing a custom PCB with nRF52840 and nRF21540 to extend the Bluetooth range

My questions are:

1) The value of components L and C in red rectangles #1, #3 and #4 is fixed and does not change for all PCB stackups and PCB layouts, right?

2) Do I need to adjust the values of the two components C21 and C18 in red rectangle #2 to for matching network to nRF21540 input TRX pin ?

3) When adjusting the values of the components in red rectangles #5 and #6 by using Vector Network Analyzer, do I need to pay attention to anything because I see they are a pair of antennas?

Best regards

Hiep Le

[Priyanka]

Hi,

We always recommend to copy the values and placements of the components in the RF as shown in the references, as these are the ones that we have tested and we recommend. So any change in these values or placement should be tested by the customer themselves and we cannot guarantee proper working.

Also, it would be difficult to copy exactly when given the differences in substrate, the number of layers, the length of transmission lines etc. So then you can try to tune the values of the components. I would recommend you to go through this PCB Guidelines first which can help a lot.

Regards,

Priyanka

[Hiep Le]

Thank you Priyanka  for your support and quick reply

But it seems the link is not working

Can you check again?

Best regards,

Hiep Le

[Priyanka]

Hi,

Apologies for the trouble. Here, attaching the link once again:  General PCB design guidelines for nRF52 series 

-Priyanka

[Hiep Le]

Thank you Priyanka