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AD7730L above 2.4576 MHz Clock Speed

Hello,

We are trying to evaluate the AD7730L for an application where we currently use an AD7730.  The datasheet implies that the AD7730L should be run at the lower 2.4576 MHz clock speed but the only explicit limits given are 1-5 MHz.

Can we run the AD7730L at 4.9152 MHz or will this damage it, or degrade the performance?  It seems like it would let us keep the same filter settings according to the excel filter model.

Thanks!

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  • Hi, 

    It is possible to run the AD7730L at 4.9152MHz since it does not exceed the 5MHz max limit. But keep in mind that running the AD7730L at 4.9152MHz will not give the optimal performance compared to AD7730 only. Since its specified frequency should be at 2.4576MHz. 

    Regards,

    Andrei

  • Hi Andrei,

    Thank you for the reply, to make sure I understand, I know the AD7730L will have more noise, etc. than the AD7730 generally.  Are you saying that it will also perform worse at 4.9152MHz than the datasheet performance in Table XXI in the datasheet, since that assumes 2.4576MHz?

    For example, if we have 2 setups:

    AD7730L at +/-10mV, CHP=1, and 100Hz Data Rate with 2.4576MHz clock
    AD7730L at +/-10mV, CHP=1, and 100Hz Data Rate with 4.9152MHz clock

    I expect the first to have 130nV RMS noise from that table, will the second have worse performance?

    Thanks,

    -chester

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  • Hi Andrei,

    Thank you for the reply, to make sure I understand, I know the AD7730L will have more noise, etc. than the AD7730 generally.  Are you saying that it will also perform worse at 4.9152MHz than the datasheet performance in Table XXI in the datasheet, since that assumes 2.4576MHz?

    For example, if we have 2 setups:

    AD7730L at +/-10mV, CHP=1, and 100Hz Data Rate with 2.4576MHz clock
    AD7730L at +/-10mV, CHP=1, and 100Hz Data Rate with 4.9152MHz clock

    I expect the first to have 130nV RMS noise from that table, will the second have worse performance?

    Thanks,

    -chester

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