Discussions AD7708 and ADUC848 crystals

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AD7708 and ADUC848 crystals

agonelli on Sep 2, 2016

Hello,

in our applications we are using 6pf and 12 pf watch crystals

We don't recognize requirements for AD7708 oscillator. Have we to use a 6pf crystal, a 12pF one or we can use both without problems?

Thank you for your help

Andrea Gonelli

jcolao

on Oct 18, 2016 1:41 AM over 4 years ago
Hi,

In the oscillator circuit section of the datasheet, the AD7708 is intended for use with 32.768khz watch crystal or ceramic oscillator.

Regards,

Jonathan
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pau_cat on Feb 22, 2017 2:11 PM over 4 years ago

Hello,

I was wondering the same as there is no explanation at all about requiered load capacitance of the crystal, so unexpected behaviour could happen in cas of strong mismatch. Please Analog staff give us more information about this topic.

Regards,

Pau.
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jcolao

on Oct 19, 2018 2:16 AM over 2 years ago in reply to pau_cat
Hi,

As mentioned in the datasheet sometimes a capacitor needs to be connected in the crystal to ensure that the resonator does not oscillate at overtones of its fundamental operating frequency. The capacitor requirement are specified usually in the crystal's datasheet.

Regards,

Jonathan
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