40 MHz Crystal mandatory?

[hassan789]

gotit.
thanks so much

[andrea.gottardo]

Hello,

Are there detailed specifications about the requirements on tolerance and stability of the oscillator?
How we could have 10ppm, on long term (10 years), if the aging of the crystal gives no less than 1ppm per year of deviation ?
Even if I choose a crystal starting with 5ppm and aging of 1ppm after ten years It reach 15ppm!

Thank you.