GROUP MEMBERS : 1. CHAUDHARI PRANAVKUMAR R.
- 230130117004
2. JADAV KANAIYABHAI R. – 230130117008
COLLEGE : GOVERNMENT ENGINEERING COLLEGE , SEC-28 , GANDHINAGAR
SUBJECT : DAC - WORKING PRINCIPLE , TYPES, ARCHITECTURE , DIAGRAM
AND INTERFACING PROGRAM
Digital to Analog Converters:
Unveiling the Magic
Explore the fascinating world of Digital to Analog Converters (DACs).
Understand how digital signals become analog outputs that power our
devices.
What is a DAC? (Digital to
Analog Converter)
Definition Purpose
A DAC converts digital Enables microcontrollers
binary data into continuous and computers to interface
analog signals. with analog devices.
Common Outputs
Voltage, current, or waveform signals for audio, control, and
sensing.
Visualizing the Process: Detailed
DAC Block Diagram Explained
1. Digital Input (fs): The original digital signal 4. D/A Converter: Converts the
at sampling rate fs modulated high-rate digital signal
to an analog signal.
2. Interpolation Filter: Increases the sampling rate 5. Analog Low-Pass Filter: Removes out-of-
by a factor of OSR (Oversampling Ratio) to reduce band noise, producing a
quantization noise. clean analog output.
3.Delta-Sigma Modulator: Shapes the quantization
noise and pushes it out of the signal band.
DAC Circuit Diagram
Analysis: Key Components
and Their Functions
Resistors Switches Amplifiers
Set precise current or Connect bits to the Sum and buffer
voltage levels for ladder or current analog signals to
binary weights. source selectively. produce final output.
DAC Working Principle: Binary Weights and
Summing Amplifiers
Binary Weights Summing Amplifier
Each bit controls a resistor weighted in powers of two. Combines weighted currents or voltages into a single analog
output.
This produces current or voltage proportional to the binary
value. Ensures linear conversion from digital input to analog signal.
The Binary-Weighted
Resistor DAC: A Simple
Implementation
Concept Operation
Uses resistors weighted as Current contributions from
powers of two for each bits add linearly at summing
digital bit. node.
Challenges
Precision resistor values needed; difficult for high bit counts.
Precision Matters: Key DAC Performance Metrics
Accuracy
Closeness of output to ideal signal,
2 reducing error.
Resolution
Defines minimum detectable voltage 1
step, measured in bits.
Linearity
3
Measures uniformity of output steps
versus digital input.
Understanding Resolution,
Accuracy, and Settling Time
Resolution Accuracy
Number of discrete output Closeness of output to the
levels, related to bit count. ideal analog value.
Settling Time
Time taken for output to stabilize within tolerance after input change.
Current Steering DACs:
High-Speed Applications
Design Speed
Uses switches to steer currents Ideal for high-frequency
from a current source array. signals and communications
systems.
Usage
Common in RF, video, and fast data converters.
Types of DAC Architectures: R-2R Ladder
Overview Advantages Disadvantages
Uses resistors of two values (R and 2R) • Simple design with fewer resistors. • Sensitivity to resistor mismatch
to convert bits into analog voltage. affects accuracy.
• Easy to manufacture and stable • Not suitable for very high-speed
performance. conversion.
R-2R Ladder DAC: Overcoming Limitations of
Binary-Weighted DACs
Structure Benefits
Uses a repetitive ladder of two resistor values: R and 2R. Simple to manufacture and scale to high resolution DACs.
Reduces resistor value variation requirements significantly. Good linearity and stable performance in various
applications.
Types of DAC Architectures:
Binary Weighted
Concept Pros
Resistors weighted in Simple and fast for low-
powers of two represent resolution DACs.
each digital bit's
contribution.
Cons
Precision degrades with high resolution due to resistor value
variation.
DAC: Types and Interfacing
Program
This presentation explores digital-to-analog converters (DACs), their
types, key specs, and interfacing methods.
Learn practical interfacing examples and software implementation for
microcontrollers.
Interfacing DAC with Microcontrollers: Overview
Communication Methods Control Signal Requirements
• Parallel interface for fast data transfer Timing and latch signals coordinate DAC data updating.
• Serial protocols like SPI and I2C for fewer pins
Power supply and reference voltage affect output stability.
Interfacing Example:
DAC0808 with Arduino
1 Pin Connections 2 Power Setup
Connect digital output pins Supply DAC0808 with dual
to DAC0808 data input pins power and reference
D0-D7. voltage.
3 Output Reading
Use analog output for waveform or voltage measurement.
Software Implementation:
Code Snippets
1 Setting Pins as 2 Writing Values
Outputs
Send 8-bit digital values to
Initialize digital pins for DAC DAC pins using digitalWrite.
data lines.
3 Timing
Use delay functions to control output waveform timing.
Applications of DACs in Real-World Systems
Audio Systems Industrial Control Measurement Equipment
Convert digital audio signals to Drive actuators and motors with Generate test signals or calibrate
analog for speakers and analog signals from digital systems. instruments requiring analog input.
headphones.
Inside the Machine: DAC
Architecture and Key
Components
Resistor Network Switch Array
Creates scaled currents or Selects resistors based on
voltages corresponding to digital input signals.
digital bits.
Output Buffer
Stabilizes and amplifies the analog signal output.
Connecting Worlds:
Interfacing DACs with
Microcontrollers
Communication Pin Configuration Data Handling
Protocols
Microcontroller sends
• SPI for fast data Proper wiring ensures digital codes
transfer accurate signal corresponding to
• I2C for simple conversion. analog levels.
wiring
Code in Action: Sample Interfacing Program
Walkthrough
Verify Output
Send Digital Data
Check analog signal with oscilloscope or
Initialize DAC
Transmit desired value to DAC via SPI or sensor feedback.
Set up communication and configure I2C.
output pins.
Summary: Key Takeaways
and Future Trends in DAC
Technology
Versatile and Critical Evolution of Precision
DACs enable smooth digital- New materials and
to-analog transitions architectures improve speed
everywhere. and accuracy.
Expanding Applications
Emerging fields like AI and IoT use DACs extensively.
.
Conclusion: Key Takeaways and Future Trends
Key Points Future Trends
• DACs convert digital data to precise analog signals. Improved resolution and speed with integrated DACs on
• Various architectures suit different accuracy and speed silicon.
needs.
Greater use in IoT, audio, and real-time control systems.
• Microcontroller interfacing is essential for embedded
applications.
THANK YOU
