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Showing content with the highest reputation on 01/15/2013 in all areas

  1. Although your question has been addressed to Torsten and since he is busy, I will be glad to take this up. Regarding your question of choice of resistors: It should not be so small that the mismatch starts playing a significant role in measurement. Should not be so large that : The input impedance of the comparator starts contribute to measurement error (one way is to avoid this to design comparator with very high input impedance - but here you will not have much choice as it will be driving gate of a MOS anyway - keep few hundred MOhms as comparator input impedance when calculating) The resistor thermal noise starts dominating. Typically resistors of the order few hundred kilo ohms would suffice. I have intentionally avoided component non-linearity and higher order poles in this solution. Please let us know if you have any doubt. Regards, Sumit
    2 points
  2. Hello, This is the case where any sampling frequency will work - simply because everything is idealistic (no bandwidth restriction which comes from comparator). There is no Vdd (apart from the supply voltage of comparator, which you are not considering), this is Vref. Reference voltage is a constant voltage. Vref can be tied with Vdd to increase input swing in some cases. I see you have beginner's hick-ups. These are very basic questions which you should either study or ask yourself. Do not start modelling anything unless you completely understand it. Please listen to following tutorial on Flash ADC: [media=] [/media]You might want to take advantage from all the videos of this channel. These videos are basically lectures from Indian Institute of Technologies which Govt. of India shares with rest of the world under right to knowledge act. Regards, Sumit
    1 point
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