Basics of ADC/DAC

作者： Pat Sagsveen 2017-09-20
标签
工程
感测
数据转换
半导体与开发工具
传感器

This blog is meant to cover the general concepts written about in the “ADC/DAC Tutorial” article. The article covers different kinds of ADC/DAC architectures, along with some of the key things to look for when choosing an ADC or DAC. I have personally had to use ADCs and DACs for several projects. A notable project was the SPEC Sensors Carbon Monoxide detector which involved a sensor with an analog output that had to be run through an ADC to my Arduino Uno. Most applications involving some kind of sensor that can interface with the real world will usually involve an ADC. DACs are very common for interfacing an MCU or Microprocessor to an analog device, like a speaker in a headset using VoIP.

Figure 1: Comparison of ADC Architectures (Courtesy of Analog Devices)

The architectures described in the article are:

  • Successive Approximation Register (SAR) ADC
  • Sigma Delta (∑∆) converter ADC
  • Pipelined converter ADC
  • Binary Weighted DAC
  • String DAC
  • R-2R DAC

    • Successive Approximation Registers, SAR

  • Most popular
  • Often use I2C or SPI interface (sometimes parallel)
  • Name comes from how value is determined by using successive approximation

    Sigma Delta,∑∆

  • Popular for high-resolution applications
  • Use oversampling
  • Use digital filtering

    • Pipelined

  • Fastest ADC
  • Uses sub ADC/DAC to easily convert most significant bits and least significant bits
  • Great for high speed applications

    • Binary Weighted DAC

  • Uses system of resistors whose outputs all meet at same summing resistor
  • More significant bits output more current than less significant bits
  • Usually used to explain DAC operation to students

    • String DAC

  • Simplest DAC architecture
  • String of equal valued resistors in series with output at each node
  • Least linear

    • R-2R

  • Very popular architecture
  • Name comes from fact that only two values of resistors are used
  • Very scalable

Figure 1 Source: http://www.analog.com/en/analog-dialogue/articles/the-right-adc-architecture.html

关于此作者

Image of Pat Sagsveen Pat Sagsveen 是 DigiKey 的助理应用工程技术员，负责协助客户寻找更好的利用新技术和新零件的方式来完成项目。他拥有俾斯麦州立大学电子与通信应用科学学士学位，2016 年毕业后即加入 DigiKey。Pat 对放大器特别感兴趣，业余花了很多时间制作和摆弄各种放大器，其中包括他制作的 3 管吉它放大器。
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