Crystal Drive Level Requirement for EZ-USB® FX2LP™ – KBA90549

Version: **

 

Question: In FX2LP™, what does it mean to have a 500 μW crystal drive level requirement?

 

Answer:

It is the maximum power dissipation in the crystal. This is one of the most important specifications for a crystal. In operation, if the power dissipated in the crystal exceeds the specified drive level, the crystal may have long-term reliability problems. The oscillation frequency may shift from the desired value, and in extreme cases the crystal may crack and stop oscillating altogether. The crystal should satisfy the following requirements:

  •   24 MHz ± 100 ppm
  •   Parallel resonant
  •   Fundamental mode
  •   12 pF (5 percent tolerance) load capacitor
  •   500 μW drive level