RF transmitter frequency problem.

[Daeho]

Dear, NORDIC manager.

Hi, I developing the our products by using the NORDIC MCU.

But, we have problem the transmitter frequency for the certification.

This problem is frequency offset of ANT pin of the nRF52832(2.4 GHz).

I saw it on the NORDIC site, but is transmitter frequency affected by the CL value of the crystal (32MHz)?

If affected, this problem is big problem?

When measured the frequency, value was 2.4GHz( +400kHz to -400kHz).

And this value was variable.

Please reply. Thank you.

[Simonr]

Hi

Yes, the capacitor values of the 32MHz crystal in your design will affect the transmitter on your device. The worst case is that the radio won't transmit at all. Even small changes to the CL values might cause issues in radio efficiency and accuracy, so you should follow this rather strictly when designing your circuit. Crystal load capacitors are determined by C1 = C2 = 2* C_L - 4 pF, where C_L is specific for the crystal. The load capacitance (C_L) should be stated in the crystal's datasheet, so you should be able to determine the correct capacitor values from there.

Best regards,

Simon

[Daeho]

Thank you, Simon. I will test it.