Applied Embedded Electronics

Chapter 7. Data Converters: ADCs and DACs

This chapter provides a brief introduction to data converters and then takes a look at some converter techniques widely used in embedded systems. “Further Reading” includes resources for those who want to take a deeper dive into converter performance and internal circuit technology.

Within an electronic system, data converters create the needed bridges between digital control and nondigital peripheral devices. The conversion of analog information to digital data is fundamental to modern electronics (Figure 7-1). Modern embedded systems interface to peripheral devices using data converters. Digital signal processing and digital control systems require interfaces to the external world. Digital-to-analog converters (DACs) and analog-to-digital converters (ADCs) provide this interface and are also used as part of drive and sense circuits.

Figure 7-1. Data converters in a system

DAC Performance Basics

As a black box, DACs can be divided into two groups:

• Nyquist rate DACs update their output once per clock cycle.

• Pulse density DACs require multiple clock cycles to achieve a stable output based upon the averaging of repetitive digital patterns. Pulse width modulation (PWM) and delta-sigma (ΔΣ) are the two methods used here.

Both Nyquist rate and pulse density DACs are commonly used in embedded systems. As of 2023, available DAC performance ...