How is the crystal drive level determined?

[pseudockb]

I am currently designing a crystal oscillator. From crystal datasheet, there is usually a specification known as drive level. Is the drive level of the crystal determined by the crystal or is it determined by the oscillator circuit design? Thank you.

 

[E-design]

Re: Crystal Drive Level

Drive level should be kept within limits suggested by the manufacturer to limit crystal dissipation due to the internal Rs. Your circuit design should limit the drive amplitude or series current.

Look at the video by Jim Williams on measuring current drive for a 32kHz crystal
"Measure nanoamps to ensure.." on this page
**broken link removed**