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  1. #1
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    Biasing an array of current steering DACs

    Hi, I would like to bias an array of 128 current steering DAC's. I have made a current source as well. How would I bias 128 DAC's using this single current source? If I bias all 128 directly, would the added capacitance create startup issues?

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  2. #2
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    Re: Biasing an array of current steering DACs

    i think you need to provide a fixed known current to each DAC individually
    so that the behavior of one DAC does not effect the behavior of another DAC

    more capacitance will likely increase start time



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    Re: Biasing an array of current steering DACs

    And even within one DAC, make sure that the voltage drop along the ground net, feeding the current sources, does ot create too large Vgs mismatch across current sources.



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  4. #4
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    Re: Biasing an array of current steering DACs

    Yes. But can I directly mirror currents to 128 DAC's from the current source? Or should I do it in stages?



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    Re: Biasing an array of current steering DACs

    You can mirror the current with 128 branches. It won't be worse from mismatch and start-up viewpoints and actually the area will be smaller compared to cascaded NMOS/PMOS mirror stages.
    If you want very fast and small DAC choose a segmented one.
    "Try SCE to AUX." /John Aaron/


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    Re: Biasing an array of current steering DACs

    Thanks.
    What exactly is the 'segmented' one?



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  7. #7
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    Re: Biasing an array of current steering DACs




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