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Is there any Dc offset on nRF52840 RF port ?

aartak gravatar image

asked 2017-09-24 09:43:40 +0100

updated 2017-09-24 09:44:20 +0100

Is there any Dc offset on nRF52840 RF port? Is it necessary to add a DC blocking capacitor if the load has DC path to ground?

In particular Is it OK to connect a 50 Ohm termination resistor after the LC impedance matching network recommended in datasheet ?

If there is a DC offset dc current will flow through the resistor and the internal circuit bias point will be shifted.

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Bjørn Kvaale gravatar image

answered 2017-09-27 11:18:21 +0100

updated 2017-09-27 12:37:22 +0100

Hi Artak! Sorry for the delayed response. Talked to a colleague here at Nordic and he said that there is no DC offset on the nrf52840 port. You therefore don't need a DC blocking capacitor or a termination resistor either. Just attach the port directly to the antenna or whatever you plan to use the RF port for. There is an internal balun that ensures a DC short to ground. There are also some customers that use DC-shorted antennas or front-end modules that wouldn't work with a DC-offset on the antenna output. Hope that answers your question.

Kind Regards,

Bjørn

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Hi Bjørn,

Thank you very much for the answer.

Regards, Artak

Artak ( 2017-09-27 18:31:47 +0100 )editconvert to answer

No problem. :)

Bjørn Kvaale ( 2017-09-28 11:40:33 +0100 )editconvert to answer

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Asked: 2017-09-24 09:43:40 +0100

Seen: 64 times

Last updated: sep. 27