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ADAU1451WBCPZ  DSP PLL Lock

Question asked by naimark on Nov 12, 2015
Latest reply on Nov 19, 2015 by naimark

 

For our new design we’re using the ADAU1451WBCPZ  DSP.

 

Unfortunately I ‘m experiencing PLL lock problem.

 

The PLL lock way form shown below:

 

 

PLL non locked.png

We’re using external clock 24.576MHZ for the 16 channels output TDM.

 

PLL fitter connection showing below:

    PLL fitter connection.png

I tried to adjust R413 in a range from 0 to 10 KOhm with no results.

 

The only if I changed C400 from 15pF to 4700pF I got clean 2V lock level.

 

Do you have any idea what is wrong?

 

Thank you

 

Mark Naiditch

 

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