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Crystal Problem

Exilis2

Oct 2, 2012
2
Joined
Oct 2, 2012
Messages
2
Hey Guys !

Im currently designing a USB-Hub with some features. The HUB-chip uses a crystal, but because its the first time i have to set up a crystal circuit im kind of confused and i cant get it working (im still studying :p)

so the chips requirements are:
Note 1 – Crystal Requirements
• Frequency accuracy: 12MHz ± 50ppm
• Load capacitance: 16pF ~ 20pF

The Crystal i have has load capacitance of 18 pF
and the accuracy is 12MHz +- 50 ppm

how can i determine which caps to use ( or not to use ) and if i need a parrallel resistor ( or not).
Like i said, first time i work with crystals and i cant find the right information on the internet. ( also the chips documentary is really thin, so im not even sure the crystal is the issue or maybe the chip isnt even starting up the crystal, but it would be nice if i knew the crystal circuit is right so i can find my error )

Thanks allready !
Jan
 

Exilis2

Oct 2, 2012
2
Joined
Oct 2, 2012
Messages
2
well, it kinda solved itself.

used 2 33 pF caps and now it works...surprise.

so the problem seems to be something different.

Thanks anyway ;)
 
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