ADAU1702 crystal startup problem

SigmaDSP & SigmaStudio SpeakerDude Apr 24, 2014 00:00 3 replies Original on forum ↗

SpeakerDude Question

Apr 24, 2014 00:00

Hi,

I am having a problem with my crystal in my ADAU1702 design. At power up the crystal does not start oscillating until I touch it with my finger.

The crystal I use is 7A-12.288MAAJ-T from TXC. According to the datasheet the load capacitance is 18pF and the shunt capacitance is max 5pF.The capacitors I use is 22pF (NP0)

What could be the reason for my oscillator not to start up properly?

Thanks and best regards

Markus

Audio Signal Processors

adau1702

SigmaDSP Audio Processors

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EEtwidget Reply

Apr 24, 2014 00:00

got a circuit to show? Sounds like maybe a ground problem? ..

Breadboard or PCB?

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SpeakerDude Reply

Apr 25, 2014 00:00

Hi,

I found another discussion with the same topic "Crystal Start-up and PCB Layout". My layout is very similar to what is discussed there - I have used vias to ground the load caps and that seem to be a problem.

I will try the patch they describe on my current board and if that solves the problem I will implement it in my next pcb run.

Thanks

Markus

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EZAdministrator Reply

Aug 2, 2018 00:00

This question has been assumed as answered either offline via email or with a multi-part answer. This question has now been closed out. If you have an inquiry related to this topic please post a new question in the applicable product forum.

Thank you,
EZ Admin

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