ADAU1446 CLKOUT modulating

Hi. I've built a prototype using the ADAU1446 using the CLKOUT as fs*256 to clock a CODEC. It's working and I'm not conscious of any problems with the output signals that might be caused by the master clock. However, CLKOUT appears to be frequency modulating at about 24kHz (fs=48kHz), the oscillator itself is stable. As best as I can tell fs is also stable. Any ideas? Is this something I'm likely to see using the fs*256 option? Would I be better using the buffered oscillator? tia Gordon

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    •  Analog Employees 
    on Feb 27, 2010 2:11 AM

    Hello Gordon,

    We haven't seen this kind of behavior on the evalution board of the ADAU1446. In order to provide you with further assistance, we'll need some more detailed information about your application and setup.

    1 - Please provide your SigmaStudio project file. If you're concerned about showing your signal flow to the public, then you can simply delete all of the cells from the schematic tab. The only information I'm really concerned about is the register settings.

    2 - Please provide a schematic or basic description of the hardware, specifically the interconnection of the ADAU1446 and the codec.

    3 - Please provide any scope shots that might help us to better understand the issue.

    Best Regards,

    Brett

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  • 0
    •  Analog Employees 
    on Feb 27, 2010 2:11 AM

    Hello Gordon,

    We haven't seen this kind of behavior on the evalution board of the ADAU1446. In order to provide you with further assistance, we'll need some more detailed information about your application and setup.

    1 - Please provide your SigmaStudio project file. If you're concerned about showing your signal flow to the public, then you can simply delete all of the cells from the schematic tab. The only information I'm really concerned about is the register settings.

    2 - Please provide a schematic or basic description of the hardware, specifically the interconnection of the ADAU1446 and the codec.

    3 - Please provide any scope shots that might help us to better understand the issue.

    Best Regards,

    Brett

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