Calculating the resolution of an 8bit DAC with 2 outputs

Discussion in 'General Electronics Chat' started by james7701, Feb 23, 2016.

  1. james7701

    Thread Starter New Member

    Jan 5, 2016
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    if i wanted to calculate the resolution of an 8bit DAC with 2 outputs do i go 2×2×2×2×2×2×2×2= 256? or can there be a shorter way?
     
  2. AnalogKid

    Distinguished Member

    Aug 1, 2013
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    The number of outputs does not affect the accuracy or precision of each one. Whether the expression is expanded or not, the theoretical limit of the accuracy of a binary converter with n bits of input or output is one part in 2^n (two to the nth power). If your calculator has a button for this, you do not need to do it the long way.

    Note that this is the theoretical limit of its accuracy. Other real world factors such as the precision of its internal resistor networks can reduce the ENOB - Effective Number Of Bits.

    ak
     
  3. james7701

    Thread Starter New Member

    Jan 5, 2016
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    no, i don't have 2^n on my calculator. i was using my cell phone while watching the video to do the calculation.
     
  4. AnalogKid

    Distinguished Member

    Aug 1, 2013
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    If you get a scientific calculator app, it usually is on there as y^x, y-to-the-y.

    2 > y^x > 8 =

    256

    ak
     
  5. kubeek

    AAC Fanatic!

    Sep 20, 2005
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    The shortest way is to remember your powers of two. Most people who work with electronics and digital stuff remember them, i would guess everything between 2^0 to 2^12 and then 2^16.
     
  6. RichardO

    Well-Known Member

    May 4, 2013
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    Are you talking about a DAC with differential outputs like a DAC-08?
     
  7. james7701

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    Jan 5, 2016
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    this is the DAC i was referring to. it wasn't made clear of the full method of calculating the resolution.
     
  8. RichardO

    Well-Known Member

    May 4, 2013
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    OK. That is not much information but it does look like it has differential outputs. Look at an Mc1408 or DAC-08 data sheet to see the difference in resolution using single-ended verses differential outputs.

    I think the resolution will be the same for both single-ended and differential configurations but you should check to be sure. What will be different is the output scaling.
     
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