antenna matching and placed components

[rico]

In the schematic of the nRF52840-DK L1 and C4 form the matching network. C22 is noted with NP, but on the DK i have, is a component placed.

Since i would like to use the MM8130-2600 connecter aswell i am interested why the additional C22 is placed on the DK.

Thanks for your support

[ketiljo]

The matching network for the nRF52840 consists of three components, C3, C4 and L1. C22 is optional:

C23 on the DK is used for antenna tuning, placed after the connector.

[rico]

My schematic of the DK looks different.

Since i will use the nrf52811, i can connect the switch directly after the matching network of C3 and L1? No need for further components?

[ketiljo]

The nRF52811 is different, this is using only two components. The reason that the nRF52840 is using three is because the 8 dBm mode needs more filtering of the harmonics. The nRF52811 has max 4 dBm.

Always refer to the specific device's reference schematic in the infocenter.