Introduction to Digital-to-Analog-Converter (DAC)

Introduction to Digital-to-Analog-Converter (DAC)

Have you heard of a Digital to Analog Converter, abbreviated as DAC? We have already discussed how Analog to Digital Converters (ADCs) convert analog signals to digital values. We will learn how to convert digital signals to analog voltages using DACs in this article.

What is a Digital-to-Analog Converter, and Where do we need it?

If you’re between the ages of, say, 12 and 60, you’re probably familiar with some analog-to-digital conversion (e.g., converting print photos to digital files or ripping .mp4s from compact discs, etc.). The digital-to-analog conversion (DAC) process accomplishes the inverse. The digital-to-analog converter requires demigod-like skills and top-of-the-line audio equipment. The method entails delving into studio-quality original master copies of digital audio tracks to locate, preserve, and amplify those tracks.

Original digital tracks contain a wealth of audio data, resulting in high-quality sound. The issue is that most of it are lost or squashed as recordings are compressed into low-byte, easily streamable formats such as.mp4. A&K expresses its commitment to sound quality by referring to the compression process as “scarification.” Since a computer is a binary machine running in an analog environment, a DAC is used to generate an output that other devices may understand.

What are the Different Types of DACs?

1.PWM DAC

It is the kind of DAC that the majority of us have unknowingly used!

  • The widely used Arduino microcontroller is capable of outputting analog signals through a PWM signal. At first glance, the PWM signal appears to be a binary waveform with just two peaks and a variable duty cycle (ratio of on-time to period). However, this is intended to be used in conjunction with an RC filter to convert the PWM signal to a voltage value by filtering out the alternating current portion and leaving the direct present component. The output voltage is in line with the input signal’s duty cycle – the higher the duty cycle, the higher the filter’s output voltage.

2.R-2R Ladder

  • It is the simplest form of DAC, requiring only two resistor values in a ladder configuration. Consider this as a very complex voltage divider, even though the math is quite involved. The binary input is routed through the 2R resistors to the Ladder’s bottom, where the output is obtained.

3.Summing Amplifier

  • The DAC is simply a weighted sum of the binary inputs, a circuit known as a summing amplifier is used. Essentially, this is an op-amp amplifier with several resistors connected to a single signal. The point at which the resistors connect is referred to as the summing junction or virtual ground. The binary input is routed through the resistors, and the analog output is collected from the op-output.
  •  Amplifier: The resistors make this circuit work; each resistor must be carefully selected and matched to obtain an accurate analog output. The more bits you have, the more resistors of different values you will require – which is not always practical. The following approach can be used to circumvent the limitations.

What is the Two Application Type of DACs?

1.Digital Power Supplies

  • The majority of microcontrollers are much too slow to be used in a power supply control loop. The relation of a power supply may be modified to alter its voltage or current output. It is accomplished by attaching a DAC to a microcontroller’s output and using it to set the reference voltage to a predetermined value.

2.Digital Signal Processing

  • It is much easier to deal with signals after they have been transformed to binary. A clear example of this is audio editing. The audio is translated to binary, after which operations can be performed on it. To playback this audio, a DAC is used to turn it into a sound signal played back on a stereo.

What is the Use of Digital to Analog Converter?

DACs are available as standalone integrated circuits or embedded in microcontrollers. However, the most often used are those that are available as a separate integrated circuit. The most frequently used are the DAC7715, DAC0832, and DAC0808. Consider the MCP4725 DAC IC for this report.

The MCP 4725 is a compact DAC module that is often used in combination with the Arduino, which is excellent news since documentation and libraries are readily accessible.

Here are some features of the DAC chip:

  1. I2C COMMUNICATION- This communication interface needs just two pins, serial data, and a serial clock, eliminating the need for additional pins on the microcontroller pulling strings. The frequency ranges between 100kHz and 3.4MHz.

2.12 BIT RESOLUTION- This is significantly better than the Arduino’s 8-bit capability. If the supply voltage is 5V, each binary digit is converted to a 5V/(212) voltage = 1.22mV, providing incredible resolution. It can enhance by lowering the supply voltage to 3.3V, which results in 0.8mV or 800V resolution.

3.PACKAGES- The MCP 4725 is available in a SOT23-6 box, which is no larger than a tiny SMD transistor, allowing for significant space savings. In general, the MCP 4725 is a powerful chip, particularly considering its size and features.

4.ADDRESS PIN- It can modify the I2C address by attaching the pin to either Vcc or GND. It is particularly advantageous when multiple devices are being used.

Disadvantages of DAC’s You Need to Know

Complexity- The majority of the DAC circuits listed above need a small number of components, which is not always practical. However, discrete DAC chips are available that communicate via SPI or I2C with a microcontroller.

Accuracy- DACs can generate only a certain number of voltage steps specified by the binary number; it is virtually impossible to generate completely continuous voltage values using DACs.

Conclusion

By transmitting a binary count to a proportional discrete voltage level, digital-to-analog converter bridge the analog and digital worlds and allow computers to communicate with equipment that operates on analog signals.

 

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