The successive approximation ADC has been the mainstay of data acquisition

systems with the clock rate of $4MHz.$ Successive Approximation Register

$($SAR$)$ supplies an approximate digital code to DAC of $V_{IN}=11\mathrm{.}2V.$ Comparison

changes digital output to bring it closer to the input value with reference voltage

$(V_{\text{R}\text{E}\text{F}})$ of $16V.$ In the figure below is the $4-$bit ADC circuit diagram, with

component values and labels.