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Unavailability of reference design crstal

Navdeep

Hi

I was designing a custom board for nrf52832. The 32MHZ crsytal mentioned in the refrence design of nrf52832 is not available on digi key. So I am ordering the below given part from digikey with same load capacitance -

https://www.digikey.ca/products/en?keywords=887-1998-1-ND

So let me know if it is a good replacement.

The reference design crystal is this:

https://www.digikey.ca/products/en?keywords=Q22FA12800025 

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    I'm sorry, but what bjorn said is incorrect.  The BLE spec calls out +/- 50kHz drift and total drift and total erro of +/- 150kHz.  At the top end of the band (worst case) this equates to +/- 20.1 ppm drift and +/- 60.4ppm total tolerance.

    While your crystal would barely satisfy the total tolerance spec it does not satisfy the drift spec.  Also, it would be a poor choice to choose a crystal where the total tolerance spec were barely met, as manufacturing variation would cause numerous out of spec devices due to load cap and pcb trace tolerances.

    Also if you choose to use 802.15.4, I should point out that 802.15.4 has an even tighter tolerance for total error of only +/- 40 ppm.

    For these reasons you should only choose crystals with 20ppm or better temp tolerance, and 20ppm or better initial offset.

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  • 0

    I'm sorry, but what bjorn said is incorrect.  The BLE spec calls out +/- 50kHz drift and total drift and total erro of +/- 150kHz.  At the top end of the band (worst case) this equates to +/- 20.1 ppm drift and +/- 60.4ppm total tolerance.

    While your crystal would barely satisfy the total tolerance spec it does not satisfy the drift spec.  Also, it would be a poor choice to choose a crystal where the total tolerance spec were barely met, as manufacturing variation would cause numerous out of spec devices due to load cap and pcb trace tolerances.

    Also if you choose to use 802.15.4, I should point out that 802.15.4 has an even tighter tolerance for total error of only +/- 40 ppm.

    For these reasons you should only choose crystals with 20ppm or better temp tolerance, and 20ppm or better initial offset.

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