Inductor in BlueNRG HF crystal circuit?

[charles23]

Posted on April 01, 2015 at 12:39

The reference schematics in AN4630 ''PCB design guidelines for the BlueNRG and BlueNRG-MS devices'' show an inductor L6 in series with one of the capacitors on the high-frequency crystal, but the app note provides no explanation for this or any value.

What is this inductor for? Should it be used? What value should be used? #bluenrg #inductor #crystal

[Nickname4847_O]

Posted on May 14, 2015 at 11:51

The inductor is used to reduce the coupling between the RF signal and the high frequency crystal that is high in some BTLE channels. Its valu depends from the layout of the board, a good starting value can be 3.9 nH