Drive level for crystals

[AlvinWong]

Hello,

I'm selecting crystals for a project with nRF52832QFAA.

I noticed that on the spec the drive levels of HFXO and LFXO are 100uW and 1uW respectively.
Should the crystals' drive levels be higher than these values?
What is the consequence of using crystals with drive levels lower than the specified values?

Thanks.

Regards,

Alvin

[Jimmywong2003]

It has the whitepaper (https://infocenter.nordicsemi.com/pdf/nwp_015.pdf?cp=12_12).
Crystal Oscillator Design Considerations

[AlvinWong]

Thanks Jimmy. It seems the white paper doesn't mention anything about drive level?