nRF21540 matching components with nRF5340

RE: nRF21540 matching components with nRF5340

Jared — Tue, 03 Jan 2023 09:56:39 GMT

Hi,

I see, the nRF5340 does not have an internal DC block, the ANT pin is DC-grounded.

regards

Jared

RE: nRF21540 matching components with nRF5340

rikhard — Tue, 03 Jan 2023 07:00:19 GMT

To make sure that powerful out of band spurious signals / jammers will not be an problem to receiver. The very selective BAW needs to have shunt inductors placed in input and output.

RE: nRF21540 matching components with nRF5340

Jared — Mon, 02 Jan 2023 09:27:04 GMT

What kind of filter and for what purpose? Additional filters is usually not needed as the matching network for the radio( L1+ C1+ L2 +C19) filters out harmonics.

best regards

Jared

RE: nRF21540 matching components with nRF5340

rikhard — Mon, 02 Jan 2023 08:26:31 GMT

Thanks for good details. One more question: does nRF5340 has internal DC block? We might have to add a filter in between nRF and xFEM and that would require shunt inductor(s) before the DC blocking capacitor.

RE: nRF21540 matching components with nRF5340

Jared — Mon, 13 Jun 2022 09:31:30 GMT

Hi,

There is mainly 3 matching networks, the first is the matching network for the radio on the nRF5340, which consists of a Pi network. Here you should follow what is recommended in the nRF5340 reference design. See the outlined components:

RF output from the matching network from the radio should be connected to the input series capacitor to the FEM:

The components marked in red should be followed as is. The components in the blue square are for matching the antenna. Here you should follow what is recommended in the datasheet of the antenna. For example in the datasheet of the 2450A T18B100 antenna, it recommends a T-network.

I hope that answers your questions.

regards

Jared