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A Presentation on 
Digital to Analog 
Conversion (DAC)
Digital to Analog Conversion (DAC) 
Submitted To: 
Shakila Naznin 
Lecturer 
Electronics & Communication Engineering Disci...
Digital to Analog Conversion (DAC) 
Submitted By: 
Shazid Reaj 
Student Id: 120914 
Dabashis Ray 
Student Id: 120905 
Abu ...
Digital to Analog Conversion (DAC) 
Outline’s 
 Basic concept about DAC 
 Application 
 Operation of Weighted Resistor ...
Digital to Analog Conversion (DAC) 
Terminology 
Analog: continuously valued signal, such as 
temperature or speed, with...
Digital to Analog Conversion (DAC) 
What is a DAC? 
A digital-to-analog converter (DAC) takes a digital code 
as its input...
Digital to Analog Conversion (DAC) 
 Digital to Analog conversion involves 
transforming the computer’s binary output in ...
Digital to Analog Conversion (DAC) 
Block Diagram 
08.09.2014 8
Digital to Analog Conversion (DAC) 
Resolution: 
Resolution is the amount of variance in 
output voltage for every change...
Digital to Analog Conversion (DAC) 
 Percentage resolution = 1 / (2n − 1), 
expressed as a percentage 
 Step size, = V/ ...
Digital to Analog Conversion (DAC) 
Resolution: Examples 
Formula 4-bit DAC 10-bit DAC 
Number of bits n 4 ? 
Number of o...
Digital to Analog Conversion (DAC) 
 Applications for Digital to Analog 
Converters: 
CCiirrccuuiitt CCoommppoonneennttss...
Digital to Analog Conversion (DAC) 
 Applications for Digital to Analog 
Converters: 
DDiiggiittaall AAuuddiioo 
 CD Pla...
Digital to Analog Conversion (DAC) 
 Applications for Digital to Analog 
Converters: 
FFuunnccttiioonn GGeenneerraattoorr...
Digital to Analog Conversion (DAC) 
 Applications for Digital to Analog 
Converters: 
MMoottoorr CCoonnttrroolllleerrss 
...
Digital to Analog Conversion (DAC) 
 Many types of DACs available 
– Binary Weighted Resistor 
– R-2R Ladder 
– Multiplie...
Digital to Analog Converter(DAC) 
Binary Weighted Resistor 
General Concept: 
 Utilizes A Inverting 
Weighted Op-amp 
Ci...
Digital to Analog Converter(DAC) 
Binary Weighted Resistor 
Binary Representation 
VREF 
Least 
Significant Bit 
Most 
Si...
Digital to Analog Converter(DAC) 
Output Voltage Analysis 
MSB LSB 
V 
V 
V 
MSB 
V IR R V 
ö çè 
÷ø 
= - = - æ + + + 
1 2...
Digital to Analog Converter(DAC) 
Binary Weighted Resistor 
FinalV Vout.Resolution OUT = 
More Generally: 
= Vref 
Resolu...
Digital to Analog Converter(DAC) 
Binary Weighted Resistor 
 Advantages 
 Simple Analysis 
 Fast Conversion 
 Disadvan...
R-2R Ladder DAC 
 Introduction: 
 Problem With The 
Weighted Resistor DAC 
Is Solved. 
 Only R & 2R Value Of 
Resistor ...
Digital to Analog Converter(DAC) 
R-2R Ladder DAC 
General Concept: 
Bit: 0 0 
0 0 
Each Bit Corresponds 
To A Switch: 
...
Digital to Analog Conversion (DAC) 
R-2R Ladder DAC 
 Current Dependent On Bits Position 
 The Current Is Divided By A F...
Digital to Analog Conversion (DAC) 
R-2R Ladder DAC 
 Analysis For Current From (001) Shown Below 
0 I 
VREF 
R 
0 I 
0 I...
R-2R Ladder DAC 
Output Analog Voltage 
 Using Thevenin’s Equivalent 
C 
D 
B 
A 
E V R V th A = 
2 ´ 
V 
0 0 R + 
R 
2 ...
Digital to Analog Conversion (DAC) 
 Similarly: 
R-2R Ladder DAC 
R 
´ 
2 0 V 
4 0 
R R 
D 
´ 
2 0 V 
2 0 
R R 
2 2 4 
D ...
Digital to Analog Conversion (DAC) 
R-2R Ladder DAC 
FinalV Vout.Resolution OUT = 
 Practically: 
= V 
Resolution n 
If, ...
Digital to Analog Conversion (DAC) 
R-2R Ladder DAC 
 Advantages 
 Only Two Resistor Values(R & 2R) 
 Does Not Require ...
Thanks 
08.09.2014 30
QQuueessttiioonnss ?? 
08.09.2014 31
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DAC-digital to analog converter

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digital to analog converter

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  • DOWNLOAD FULL BOOKS, INTO AVAILABLE FORMAT ......................................................................................................................... ......................................................................................................................... 1.DOWNLOAD FULL. PDF EBOOK here { https://tinyurl.com/y3nhqquc } ......................................................................................................................... 1.DOWNLOAD FULL. EPUB Ebook here { https://tinyurl.com/y3nhqquc } ......................................................................................................................... 1.DOWNLOAD FULL. doc Ebook here { https://tinyurl.com/y3nhqquc } ......................................................................................................................... 1.DOWNLOAD FULL. PDF EBOOK here { https://tinyurl.com/y3nhqquc } ......................................................................................................................... 1.DOWNLOAD FULL. EPUB Ebook here { https://tinyurl.com/y3nhqquc } ......................................................................................................................... 1.DOWNLOAD FULL. doc Ebook here { https://tinyurl.com/y3nhqquc } ......................................................................................................................... ......................................................................................................................... ......................................................................................................................... .............. Browse by Genre Available eBooks ......................................................................................................................... Art, Biography, Business, Chick Lit, Children's, Christian, Classics, Comics, Contemporary, Cookbooks, Crime, Ebooks, Fantasy, Fiction, Graphic Novels, Historical Fiction, History, Horror, Humor And Comedy, Manga, Memoir, Music, Mystery, Non Fiction, Paranormal, Philosophy, Poetry, Psychology, Religion, Romance, Science, Science Fiction, Self Help, Suspense, Spirituality, Sports, Thriller, Travel, Young Adult,
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DAC-digital to analog converter

  1. 1. A Presentation on Digital to Analog Conversion (DAC)
  2. 2. Digital to Analog Conversion (DAC) Submitted To: Shakila Naznin Lecturer Electronics & Communication Engineering Discipline Khulna University. Khulna. 08.09.2014 2
  3. 3. Digital to Analog Conversion (DAC) Submitted By: Shazid Reaj Student Id: 120914 Dabashis Ray Student Id: 120905 Abu Jubair Obhi Student Id: 120901 2nd Year, Term II Electronics & Communication Engineering Discipline, Khulna University. Khulna. 08.09.2014 3
  4. 4. Digital to Analog Conversion (DAC) Outline’s  Basic concept about DAC  Application  Operation of Weighted Resistor DAC  Operation of R-2R Ladder DAC 08.09.2014 4
  5. 5. Digital to Analog Conversion (DAC) Terminology Analog: continuously valued signal, such as temperature or speed, with infinite possible values in between. Digital: discretely valued signal, such as integers, encoded in binary. digital-to-analog converter: DAC, D/A, D2A Real world (lab) is analog V Computer (binary) is digital t V 08.09.2014 5
  6. 6. Digital to Analog Conversion (DAC) What is a DAC? A digital-to-analog converter (DAC) takes a digital code as its input and produces an analog voltage or current as its output. This analog output is proportional to the digital input. DAC 100101… 08.09.2014 6
  7. 7. Digital to Analog Conversion (DAC)  Digital to Analog conversion involves transforming the computer’s binary output in 0’s and 1’s (1’s typically = 5.0 volts) into an analog representation of the binary data  DAC: Vmax  n digital inputs for digital encoding x0 x1  analog input for Vmax … DAC Xn-1  analog output a a  General Concept: 08.09.2014 7
  8. 8. Digital to Analog Conversion (DAC) Block Diagram 08.09.2014 8
  9. 9. Digital to Analog Conversion (DAC) Resolution: Resolution is the amount of variance in output voltage for every change of the LSB in the digital input.  Just as with ADCs, there are several common ways of specifying a DAC’s resolution:  Number of bits, n  Number of output codes = 2n, or number of steps in the output = 2n − 1 08.09.2014 9
  10. 10. Digital to Analog Conversion (DAC)  Percentage resolution = 1 / (2n − 1), expressed as a percentage  Step size, = V/ (2n − 1) ref Example: Find out the percentage resolution of a DAC of n bits, and hence determine the value for n = 12. Solution: Percentage resolution = 1 ´ 100% 2 n - 1 For n = 12, Percentage resolution = 1 12 ´ = = - 100% 0.0244% 244ppm (part per million) 2 1 08.09.2014 10
  11. 11. Digital to Analog Conversion (DAC) Resolution: Examples Formula 4-bit DAC 10-bit DAC Number of bits n 4 ? Number of output 2n 16 ? codes Number of steps in 2n−1 15 ? the output Percentage 1 / (2n−1) 1/15 ? resolution Step size (assuming V/ 2n-1 V/ 15 ? 5 V reference ref ref voltage) 08.09.2014 11
  12. 12. Digital to Analog Conversion (DAC)  Applications for Digital to Analog Converters: CCiirrccuuiitt CCoommppoonneennttss  Voltage controlled Amplifier  digital input, External Reference Voltage as control  Digitally operated attenuator  External Reference Voltage as input, digital control  Programmable Filters  Digitally controlled cutoff frequencies 08.09.2014 12
  13. 13. Digital to Analog Conversion (DAC)  Applications for Digital to Analog Converters: DDiiggiittaall AAuuddiioo  CD Players  MP3 Players  Telephone 08.09.2014 13
  14. 14. Digital to Analog Conversion (DAC)  Applications for Digital to Analog Converters: FFuunnccttiioonn GGeenneerraattoorrss  Digital Oscilloscopes Digital Input Analog Output  Signal Generators  Sine wave generation  Square wave generation  Triangle wave generation  Random noise generation 08.09.2014 14
  15. 15. Digital to Analog Conversion (DAC)  Applications for Digital to Analog Converters: MMoottoorr CCoonnttrroolllleerrss  Cruise Control  Valve Control  Motor Control 08.09.2014 15
  16. 16. Digital to Analog Conversion (DAC)  Many types of DACs available – Binary Weighted Resistor – R-2R Ladder – Multiplier DAC – Non-Multiplier DAC • Among them Weighted & R-2R are commonly used. 08.09.2014 16
  17. 17. Digital to Analog Converter(DAC) Binary Weighted Resistor General Concept:  Utilizes A Inverting Weighted Op-amp Circuit.  Weighted Resistors Are Used To Distinguish Each Bit From The Most Significant To The Least Significant Rf R 2R V o -VREF å i I LSB 4R 8R MSB 08.09.2014 17
  18. 18. Digital to Analog Converter(DAC) Binary Weighted Resistor Binary Representation VREF Least Significant Bit Most Significant Bit SET CLEARED ( 1 1 1 1 )2 = ( 15 )10 08.09.2014 18
  19. 19. Digital to Analog Converter(DAC) Output Voltage Analysis MSB LSB V V V MSB V IR R V ö çè ÷ø = - = - æ + + + 1 2 3 4 R R R R 2 4 8 out f f LSB V K 1 13 V K = -æ ´ + ´ + ´ + ´ ö çè = - ÷ø out K K 1 10 K K K K 0 10 10 5 1 10 2.5 10 1.25 08.09.2014 19
  20. 20. Digital to Analog Converter(DAC) Binary Weighted Resistor FinalV Vout.Resolution OUT = More Generally: = Vref Resolution n - 2 1 If, Vref = 13 Then resolution for 4 bit = V 13 = - Then binary 1111(15V) is 0.867 16 1 V 10 K ö çè out = - V V K K K 1 10 K K K K 13 1 .867 1 10 10 5 1 10 2.5 1.25 out ´ ÷ø = -æ ´ + ´ + ´ + ´ 08.09.2014 20
  21. 21. Digital to Analog Converter(DAC) Binary Weighted Resistor  Advantages  Simple Analysis  Fast Conversion  Disadvantages  This setup requires a wide range of accurate values of resistors  A 10 bit DAC needs resistors ranging from R to R/1024.  Requires low switch resistances in transistors  Usually limited to 8-bit resolution. 08.09.2014 21
  22. 22. R-2R Ladder DAC  Introduction:  Problem With The Weighted Resistor DAC Is Solved.  Only R & 2R Value Of Resistor Are Required. Vout Digital to Analog Converter(DAC) 08.09.2014 22
  23. 23. Digital to Analog Converter(DAC) R-2R Ladder DAC General Concept: Bit: 0 0 0 0 Each Bit Corresponds To A Switch: Cases: Bit Is High Bit Is Low 4-Bit Converter Vref 08.09.2014 23
  24. 24. Digital to Analog Conversion (DAC) R-2R Ladder DAC  Current Dependent On Bits Position  The Current Is Divided By A Factor Of 2 At Each Node 08.09.2014 24
  25. 25. Digital to Analog Conversion (DAC) R-2R Ladder DAC  Analysis For Current From (001) Shown Below 0 I VREF R 0 I 0 I 0 I R R R 2R 2R 2R 2R Op-Amp input “Ground” B0 2 4 8 B1 B2 0 I 2 08.09.2014 25
  26. 26. R-2R Ladder DAC Output Analog Voltage  Using Thevenin’s Equivalent C D B A E V R V th A = 2 ´ V 0 0 R + R 2 2 2 = = R R th =  Equivalent Circuit : C B D Digital to Analog Conversion (DAC) 08.09.2014 26
  27. 27. Digital to Analog Conversion (DAC)  Similarly: R-2R Ladder DAC R ´ 2 0 V 4 0 R R D ´ 2 0 V 2 0 R R 2 2 4 D C R E V V th B = + = = R ´ 2 2 0 D R R th = 2 2 8 E V V th C = + = = 0 V R R 2 2 4 E V V th B = + = = R R th = R R th = OUT V ù úû 0 1 2 3 V D D D D R = · é + + + êë 16 8 4 2 f TotalV ref R OUT D is the binary input 08.09.2014 27
  28. 28. Digital to Analog Conversion (DAC) R-2R Ladder DAC FinalV Vout.Resolution OUT =  Practically: = V Resolution n If, = 5V Then resolution for 4 bit = Then binary 13V is 0 - 2 1 0 V 0.334 V 5 = - 16 1 V 10 K out = ö çè V V K K K 1 10 K K K K 4.342 1 .334 0 10 10 5 1 10 2.5 1.25 out ´ ÷ø = æ ´ + ´ + ´ + ´ 08.09.2014 28
  29. 29. Digital to Analog Conversion (DAC) R-2R Ladder DAC  Advantages  Only Two Resistor Values(R & 2R)  Does Not Require High Precision Resistors.  Disadvantages  Lower Conversion Speed Than Binary Weighted DAC 08.09.2014 29
  30. 30. Thanks 08.09.2014 30
  31. 31. QQuueessttiioonnss ?? 08.09.2014 31

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