Frequency Correction on Production Line for each boards to reduce the frequency offset issues

RE: Frequency Correction on Production Line for each boards to reduce the frequency offset issues

Susheel Nuguru — Mon, 28 Nov 2022 11:27:12 GMT

I have requested my colleague who is the Regional Sales Manager of India to reach you out for helping you with this request. If you want to contact him yourself, please write to gaurav.kapoor@nordicsemi.no

RE: Frequency Correction on Production Line for each boards to reduce the frequency offset issues

VishnuPrasad V — Mon, 28 Nov 2022 10:13:26 GMT

Hi Susheel,

Do you have any testing facilities inside India?

As we are from India that will be easy.

If not, Where is the lab to which we need to send the Boards?

Thanks!

RE: Frequency Correction on Production Line for each boards to reduce the frequency offset issues

VishnuPrasad V — Mon, 28 Nov 2022 10:05:55 GMT

Hi Susheel,

Thanks for the Data.

RE: Frequency Correction on Production Line for each boards to reduce the frequency offset issues

Susheel Nuguru — Mon, 28 Nov 2022 09:01:07 GMT

Suggestions from our hardware expert

The frequency offset is dependent on the accuracy of the HFXO, this is tuned by changing the load capacitance on each of the XO lines. The values of these capacitors is dependent on the crystal, and may not match the 12pF we have in the reference design. To calculate a good starting point for these values we have a equation in the PS:

Where C1 and C2 are the capacitors needed, Cpin is the pin capacitance listed in the PS, CL is listed in the crystal datasheet, Cpcb1 and Cpcb2 is the trace capacitances.

Assuming 0 trace capacitance and specifying C=C1=C2 the equation can be simplified to:

C = 2*CL-Cpin

This will give a good staring point, but may need to be tuned if the Cpcb cant be neglegted.

We tune this as a part of the radio and antenna tuning, so you can send boards to us if you don't have the equipment needed(spectrum analyzer)

RE: Frequency Correction on Production Line for each boards to reduce the frequency offset issues

Susheel Nuguru — Mon, 28 Nov 2022 07:39:32 GMT

I am not 100% sure on this, let me ask my colleague and come back to you today.

RE: Frequency Correction on Production Line for each boards to reduce the frequency offset issues

VishnuPrasad V — Tue, 22 Nov 2022 15:58:02 GMT

Hi Susheel,

Thanks for the Quick response.

If all the design of HW is done according to how nordic suggested, what is the expected offset range?

Thanks!

RE: Frequency Correction on Production Line for each boards to reduce the frequency offset issues

Susheel Nuguru — Tue, 22 Nov 2022 11:44:46 GMT

It should be enough for you to check the frequency of the configured radio and this can be sniffed through radio register. You can try to use nRF5340 to have more advance frequency calibration capabilities

RE: Frequency Correction on Production Line for each boards to reduce the frequency offset issues

Susheel Nuguru — Tue, 22 Nov 2022 11:39:25 GMT

This is unfortunately not possible to do with this solution.