8-bit DAC Digital to Analog Converter Design with Resistor Ladder Explained

How to design a Digital to Analog converter using an R-2R resistor ladder is discussed in this unipolar DAC circuit design tutorial video using an 8-bit Data Converter example. This DAC circuit is implemented using two Op Amp, an R-2R ladder resistor network and 8 switches controlled by the 8-bit input digital codeword. For more Op Amp and circuit examples see • Electrical Engineering... . This Digital to Analog conversion tutorial video shows how this DAC circuit is linearly converting the input 8-bit digital codeword to a unipolar analog voltage at the output of the circuit. There are two operational amplifier stages in this circuit. The first op amp stage is an inverting amplifier that converts the input positive reference voltage to an intermediate negative voltage at the input of the ladder resistor network. The resistor network then breaks down the resulting input current into smaller terms that are scaled down versions of the input current by powers of two (binary math). The Most Significant Bit (MSB) of the applied digital codeword controls the left-most switch and the Least Significant Bit (LSB) controls the right-most switch in this DAC circuit. As explained, the switches don't change the branch current values and instead they just divert the current from or to the output of the output stage Operational amplifier. The formula for the resulting analog output voltage is computed using a combination of Kirchhoff circuit laws KCL and KVL , and op amp virtual short and virtual ground for the inverting amplifier and current summing amplifier stages in this circuit.

[@STEMprof]

Thanks for watching. For more Digital and Analog Signal Processing & Circuit examples please see:
Digital Filter Cascade Implementation Example ua-cam.com/video/S5ev43KQJmY/v-deo.html
Digital Filter Design using MATLAB filter Designer Tool ua-cam.com/video/dSZmymGa3Wo/v-deo.html
For Analog Signal Processing examples please see
Op Amp Amplifier with Electronic Gain Control ua-cam.com/video/NoNgQpbj77Y/v-deo.html
Logarithm Analog Computer with Op Amp ua-cam.com/video/RpKEq5WyoLg/v-deo.html
Analog Computer to Raise Signal to power n ua-cam.com/video/IUTlBH1UraE/v-deo.html
Analog Computer solves Differential Equation ua-cam.com/video/ENq39EesfPw/v-deo.html
Voltage Regulator Design with Op Amp and BJT Transistor ua-cam.com/video/rI9f6-DyXxQ/v-deo.html
How to find Bode Plot, Freq Response, Transfer Function of Analog Filters ua-cam.com/video/vZFkPeDa1H8/v-deo.html
Universal Analog Filter Design ua-cam.com/video/2J-0msXZE2o/v-deo.html
Laplace Transform Example and S-domain circuit analysis: ua-cam.com/video/ps8N5TPM_qU/v-deo.html
Op Amp circuit Bode Frequency plot ua-cam.com/video/BLVzuuqAlZs/v-deo.html
Analog Logarithm Computer ua-cam.com/video/RpKEq5WyoLg/v-deo.html
Lowpass Butterworth Filter: ua-cam.com/video/UzCjkwqy-9w/v-deo.html
Analog Computer to Raise Signal to power n ua-cam.com/video/IUTlBH1UraE/v-deo.html
Triangle Oscillator Op Amp circuit ua-cam.com/video/JF5Up_cuL9k/v-deo.html
Differential Equation Solver Analog Circuit ua-cam.com/video/R3X5AYNZGEI/v-deo.html
Complex Sinusoid Oscillator ua-cam.com/video/GXRhmwmS5Zk/v-deo.html
Sawtooth Oscillator Design ua-cam.com/video/2eUsGPfqbW4/v-deo.html
Full-Wave Rectifier circuit example ua-cam.com/video/DJJMNU-CYcg/v-deo.html
Sawtooth Waveform Generator design with OpAmp, JFET, BJT ua-cam.com/video/5zHXTx-Vl20/v-deo.html
op amps Circuit with feedback loops to design an analog computer that solves a second order differential equation ua-cam.com/video/HeZRtnRXpEI/v-deo.html
For more analog circuits and signal processing examples see: ua-cam.com/play/PLrwXF7N522y4c7c-8KBjrwd7IyaZfWxyt.html
Digital Filter: Direct Form vs Transpose Form ua-cam.com/video/ekvY-ctW6Js/v-deo.html
For more Digital Signal Processing and DSP examples please see ua-cam.com/play/PLrwXF7N522y6cSKr0FmEPP_zQl011VvLr.html
I hope these Digital and Analog Circuit design and analysis videos are interesting. 🙋‍♂

[@twin1q]

The inverted r-2r has a huge advantage of not changing the current for all the strings. The biggest challenge with this circuit is the glitches. Brings me back to my AMS design classes.

[@STEMprof]

Thanks for watching and sharing your thoughts. Glad that this DAC design with R-2R ladder resistor network is interesting. To your point, there are many practical considerations that need to be taken into account for integrated circuit implementation of this design. Matching resistors and techniques to deal with mismatches and switch non-idealities are important concerns. For more examples please see the Analog circuits playlist ua-cam.com/play/PLrwXF7N522y4c7c-8KBjrwd7IyaZfWxyt.html and my digital signal processing playlist ua-cam.com/play/PLrwXF7N522y6cSKr0FmEPP_zQl011VvLr.html . I hope these engineering, design and analysis examples are useful and interesting. 🙏

[@amanruke3961]

❤❤❤

[@STEMprof]

Thanks for watching. Glad that you like this Digital to Analog Converter (DAC) Circuit Design Tutorial using R-2R ladder resistor network with two operational amplifiers. For more analog circuits and signal processing examples see: ua-cam.com/play/PLrwXF7N522y4c7c-8KBjrwd7IyaZfWxyt.html and for more Digital Signal Processing and DSP examples please see ua-cam.com/play/PLrwXF7N522y6cSKr0FmEPP_zQl011VvLr.html
I hope these videos are interest as well. 🙂

[@zaiddaman6073]

Thank you sir 🙏

[@STEMprof]

You're welcome! Glad that this DAC video is useful. For more circuit examples see the ua-cam.com/play/PLrwXF7N522y4c7c-8KBjrwd7IyaZfWxyt.html circuit videos playlist.

[@dimzen5406]

In the days of my youth there was "Covox" DAC that can be snapped to old printer output in order to convert to line output, kinda soundcard for the poor 😂

[@STEMprof]

Thanks for watching and sharing your experiences. I am almost an old-timer myself :) I haven't forgotten the days of punch cards and VAX Computing Systems with Tube monitors 😄. I hope you also find interesting my recently posted video of Push-Pull Power Amplifier Design with Op Amp, Sziklai Darlington Transistors ua-cam.com/video/8BFzsi7-Vbs/v-deo.html

[@AnalogDude_]

it would be big if you use 3 x CD4053 or you know any other SPDT ic?

[@STEMprof]

Thanks for watching and your good question. I wouldn't recommend Discrete implementation of this ladder resistor DAC (unless done purely experimental). The integrated circuit implementation allows super compact realization of the needed analog multiplexers with transistors. There are also alternative implementation of R-2R ladder DAC that are more Discrete design friendly. I will post another example soon. For more circuit examples please see ua-cam.com/play/PLrwXF7N522y4c7c-8KBjrwd7IyaZfWxyt.html . I hope this helpful. 🙋‍♂️