Hello Martin,
Hope you are doing well.
Generally the crystal tolerance is not specified in the datasheet because it may vary with each custom application. The tolerance and frequency ranges are established mainly by the communication protocols used. USB and Ethernet are usually the strictest in regards to the frequency tolerance. A good rule of thumb would be to work with the strictest as your max and then decide on the crystal of your preference. For USB, I'd recommend +/-50ppm or better, consequently the rest of the peripherals will work as expected.
In the hardware development guide, we recommend the following parameters:
connect a fundamental-mode crystal between XTALI and XTALO. A typical 80 ESR crystal rated for a maximum drive level of 250 μW is acceptable. Alternately, a typical 50 ESR crystal rated for a maximum drive level of 200 μW may be used.
The crystal we use on the evaluation board has the following specifications:
As you may see the tolerance is 20ppm and the ESR and DL are meet the hardware recommendations.
Best Regards,
Sabina
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Hello Martin,
Hope you are doing well.
Generally the crystal tolerance is not specified in the datasheet because it may vary with each custom application. The tolerance and frequency ranges are established mainly by the communication protocols used. USB and Ethernet are usually the strictest in regards to the frequency tolerance. A good rule of thumb would be to work with the strictest as your max and then decide on the crystal of your preference. For USB, I'd recommend +/-50ppm or better, consequently the rest of the peripherals will work as expected.
In the hardware development guide, we recommend the following parameters:
connect a fundamental-mode crystal between XTALI and XTALO. A typical 80 ESR crystal rated for a maximum drive level of 250 μW is acceptable. Alternately, a typical 50 ESR crystal rated for a maximum drive level of 200 μW may be used.
The crystal we use on the evaluation board has the following specifications:
As you may see the tolerance is 20ppm and the ESR and DL are meet the hardware recommendations.
Best Regards,
Sabina
-----------------------------------------------------------------------------------------------------------------------
Note: If this post answers your question, please click the Correct Answer button. Thank you!
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