nRF52832 FCC failed

RE: nRF52832 FCC failed

Andreas — Mon, 06 Aug 2018 07:58:53 GMT

Hi Ye-Sheng,

The pattern you see should be much more constant, no ripple in the level. There is a component at -128 MHz, but it should not be this high, it might be that the ripple level builds on top of this. Have you measured the output of the nRF52 to determine if it originates from the nRF52 or the FEM?

Best regards,

Andreas

RE: nRF52832 FCC failed

Ye-Sheng — Thu, 02 Aug 2018 06:38:06 GMT

Andreas,

Thanks for your suggestion. We tried to populate 100 nF on DEC2, but the result remains the same. The above plot is measured with ICASH on already. It gets worse if we turn off ICASH indeed.

Further things we can try?

Thanks,

Ye-Sheng

RE: nRF52832 FCC failed

Andreas — Fri, 27 Jul 2018 08:45:49 GMT

Hi,

This is a harmonic originating from the clock system. You can try to enable ICACHE and populate 100 nF on DEC2, this should reduce the level of it by a couple of dB.

Best regards,

Andreas