About NRF52810 transmit power question.

[link.he]

Now I have a problem, the transmitting power of NRF52810-QCAA is too low, only -2.73dBm. I tried to adjust the value of the capacitor, but the effect was not obvious. Excuse me, in this case, can we replace the 3.9Nh inductor with a greater inductive value?

[ketiljo]

This can be an issue with the layout if you see output power this low. Can you post the layout please? Also the schematic is usefull.

You need to measure the harmonics as well when you change the values of the component in the matching network.

[link.he]

Hello Ketiljo

Thank you for your reply. I have used a new test point and the transmitting power has actually increased.

I'm using a conductive emission mode, using a spectrum analyzer to measure the emission power.

The first point I tested was L2 inductor back end and C18 capacitor, transmitting power around -3dbm.

Later I tested the C20 capacitor ends. The transmitting power is about -1dbm. Which one shall prevail?

[ketiljo]

You must test after L2 with L2 and C20 removed:

Some of the problem is that your C18 isn't correctly grounded. It should not be connected to the ground plane, only to the VSS_PA pin and the center pad, like Ce in the reference layout: 

Try to cut the ground plane near C18

What output power setting are you using? Unmodulated or modulated carrier?

[link.he]

Hello Ketiljo

Thank you for your reply.

C20 and L3 were removed during my tests.

A modulated carrier is used and the transmitted power is set at 0dBm.

I understand the problem about C18 now

Thank you for your support

[ketiljo]

See what happens if you cur the ground plane near C18. What's the level of the harmonics?

When you measure the peak power of a modulated carrier, you will see less power than if you do the same on a unmodulated carrier. The power is the same, just spread out on frequency.