DAC ADC Successive Approximation

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Steve1992

Joined Apr 7, 2006
100
In a DAC practical circuit I read the 'step' change in Vout can be given as:

Vstep = Vref/2^n

where n is the number of bits in the digital word.

Eg.
Vref = 5V
n = 8-bits

5V/256 = 19.5mV

41(decimal) x 19.5mV = 800mV.



Is it OK to use this same procedure for ADC successive approximation circuit calculations?

Eg.
Vsig = 3.6V
8-bit, 5V ADC

5V/256 = 19.5mV

Vsig/19.5mV = 183(decimal)
 

MrChips

Joined Oct 2, 2009
30,709
Let us take a simple example.
Suppose we have a 2-bit DAC with full-scale range of 0-3V.
Is the step size 3/4 V or 3/3 V?
 
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