What is the input impedance of nrf52840 in different modes

RE: What is the input impedance of nrf52840 in different modes

ramduv — Thu, 19 Dec 2019 09:24:54 GMT

Hi,

Do you have the same info for WLCSP SoC as it is different for this ANT pin?

Thanks

Ramesh

RE: What is the input impedance of nrf52840 in different modes

nataddrho — Mon, 30 Sep 2019 12:56:36 GMT

The output impedance of the ANT pin of the nRF52840 at TX power of 0dBm is 115.771 + 33.357j ohms.

See page 3 of Nordic's measurement file nRf52840 QIAA matching network.pdf (in the .rar compressed file linked in this thread). Their measured value looking into the matching network from the ANT pin is 115.771 - 33.357j ohms.

The impedance of the matching network (0.8pF shunt, 3.9nH series) of the suggested nRF52840 layout is 111.8 - 32.9j with a 50 ohm load, which verified the measured number above. The complex conjugate should be the impedance of the ANT pin.

The impedance of the ANT pin seems to be different for TX powers other than 0dBm, but this is the most common transmit power.

RE: What is the input impedance of nrf52840 in different modes

Joakim Jakobsen — Wed, 24 Oct 2018 08:00:03 GMT

Hi.

Please take a look at the documents in the attached folder. You should be able to find the information you need there.

devzone.nordicsemi.com/.../nRF52840-QIAA-matching-network.rar

Best regards,
Joakim

RE: What is the input impedance of nrf52840 in different modes

jjvicentenavarrete — Mon, 22 Oct 2018 14:35:42 GMT

Hi, I also need the output impedance of the ANT port in order to get my matching network calculated.

Sometimes, the design has to be slightly different from the reference design, and having no output impedance data makes it impossible to get the maximum output power and thus not the best solution.

Please, this info is important if it isn´t 50 Ohm (which I assume it isn´t).

Best Regards,

Juanjo

RE: What is the input impedance of nrf52840 in different modes

dom — Fri, 23 Mar 2018 17:51:08 GMT

Joakim,

Any updates on this now that the nRF52840 is released? I've noticed several different forum users are interested in this data, myself included.

Thanks,

Dom

RE: What is the input impedance of nrf52840 in different modes

Joakim Jakobsen — Thu, 16 Nov 2017 13:20:18 GMT

Hi Sasi!

Sorry for the late response!

We don't provide data for this yet, because we haven't measured it yet.
This should however be available in the specification at a later point in time.

Best regards.
Joakim.