layout of crystals for NRF52

[yulya]

HI, I saw in a recommended layout for NRF52, that the traces goes as follow:

1. the side that closed to NRF passes through load capacitor and then goes to the connected pin of Crystal.
2. the side that is palced more far away, the trace goes first to the connected pin and then to the capacitor.

Is there a purpose in this kind of layout? From my previous designs i know that it is recommended first to go through the crystal pin and then to the load capacitor and here we have one pin this way and the other opposite.

thank you Yulya

[FormerMember]

The purpose of having the reference layout that is most likely the following:

• The order of crystal + capacitor: I would that ideally it would perhaps have been better to have the capacitor "before" the crystal, but in reality it doesn't matter that much because the frequency of the signal is not that high.

• Size: Size is an important factor. We want the reference layout to be as compact as possible (while still making it work very well).

You can test that the crystal + load capacitors work well by setting the radio in TX mode, and verify that it transmits at the correct frequency (has little offset).