AD7730: Required capacitance across the XTAL/ Resonator

Document created by analog-archivist Employee on Feb 23, 2016
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I want to use a 4.91 Mhz ceramic resonator from Murata, which has integrated
capacitors, to earth of 15pF. How can I be sure, this will startup probably?
What is the recommendation for the Xtal and related capacitors.

 

The crystal or ceramic resonator is connected across the MCLK IN and MCLK OUT
pins, as per Figure 17.
Capacitors C1 and C2 on the XTAL may or may not be required and may vary in
value depending on the crystal/resonator manufacturer's recommendations. So
therefore in this case as the capacitors are integrated this is not an issue.
The AD7730 has a capacitance of 5 pF on MCLK IN and 13 Pf on MCLK OUT so, you
could check with Murata if this additional capacitance will effect to get the
crystal/resonator operating at its correct frequency.

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