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Choosing crystal for RX circuit

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johndeaton

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I am designing a receiver circuit around a RF receiver chip. The app note in the datasheet specifies a crystal with a 20ppm tolerance. However, the best I can find on Digikey and Mouser is 30ppm. Will this part work ok or do I need to keep searching?

Thanks
 

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Depends on many parameters like

- receiver bandwidth
- utilized temperature range
- possible channel assignment in utilized RF band
 

SunnySkyguy

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YOu can't make an Xtal 20 ppm over a wide temperature range due to the 3rd order variations with different cuts.
You can get a 25ppm tolerance at room temp and a 25 ppm over a wide temp range and design a compensation and null offset circuit.

But no need now.

For about $2~4 now you can get a 0.5 to 10ppm TCXO which is temperature compensated at D-K

Use one of these. https://www.digikey.com/product-sea...=0&rohs=0&quantity=1&ptm=0&fid=0&pageSize=500



Of course if this just for room temp, a Varicap or trimcap can null any offset 50 ppm or whatever.
 

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