Does changing the crystal frequency from 32MHz to 31.5MHz affect PLL or radio performance?

[jklane]

I'm interested in operating the radio off of 32 MHz to avoid multiples of 128MHz. One options being considered is utilizing an external crystal of a slightly different frequency, such as 31.5MHz. Would a change such as this significantly alter performance of the PLL or radio? Are there other better options to consider?

Thank you

[Andreas]

Hi,

 

The nRF52 series is designed to use a 32 MHz crystal with accuracy of less than +/-60 ppm. Using anything else, e.g. 31.5 MHz, the oscillator might not work, and even if it might cause timing violations causing digital issues, CPU lockup etc. Furthermore the radio will not work as it should.

 

Best regards,

Andreas