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The Designer's Guide Community Forum
https://designers-guide.org/forum/YaBB.pl Design >> Analog Design >> Mismatch of Resistors in Resistor string DAC https://designers-guide.org/forum/YaBB.pl?num=1185413144 Message started by hchanda on Jul 25th, 2007, 6:25pm |
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Title: Mismatch of Resistors in Resistor string DAC Post by hchanda on Jul 25th, 2007, 6:25pm Hello All, I am trying to understand how mismatch in resistors would affect the performance of resistor string DAC. Suppose if the DAC assures the voltage range between V1 and V2 , will mismatch between the resistors affect the voltage range? Is it going to affect the DAC step size and linearity? I would like to get a clear picture of how mismatch between resistors would affect the resistor string DAC performance? Appreciate your time. |
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Title: Re: Mismatch of Resistors in Resistor string DAC Post by boe on Jul 26th, 2007, 4:41am Hello hchanda, hchanda wrote on Jul 25th, 2007, 6:25pm:
Voltage range and (nominal) step size are unaffected by mismatch, as they are defined by the voltages at the end of your R string and the number of unit res's. Monotonicity is also structurally guaranteed. Mismatch results in INL and DNL. BOE |
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Title: Re: Mismatch of Resistors in Resistor string DAC Post by topquark on Jul 26th, 2007, 4:58am In general, in order to appreciate the effect of spreading of R-values on the monotonicty of the DAC, you have to rely on monte carlo sims. Run a mc analysis as you switch from one R value to the next bit. See the distribution of voltage or current or gain you're interested in. As you go from nth bit to (n+1) th bit- smaller the spread, the better. Foir e.g μ(n) + 3σ should be < μ(n+1) - 3σ Hope this helps. |
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Title: Re: Mismatch of Resistors in Resistor string DAC Post by hchanda on Jul 26th, 2007, 10:55am Thanks a lot BOE and Topquark. |
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