Analog-to-digital
converters (ADCs) are one of the most commonly used blocks in embedded
systems. Applications of ADCs include current sensing, motor control,
temperature sensing and a myriad of others. As a consequence,
understanding the basic specifications of an ADC and selecting an
appropriate device for the given application is a must for reliable
operation and cost-effective design.
This
series of articles begins with the basics of ADCs, and then discusses
different characteristics of an ADC that are important to design,
including the impact of various irregularities, types of ADCs available
on the market, advantages and disadvantages of each type, and how their
selection varies from application to application.
The first part of this article series discusses what exactly an ADC is and how an ideal ADC works. The second part
explores the "simple" specification of sample rate, along with the
considerations that affect selecting the converter to match your needed
rate, such as the Nyquist rate, undersampling, and aliasing. The third part looks at offset errors and calibration, and the fourth part looks at gain error and drift in that error. The fifth part is a look at two related and sometimes confused nonlinearities in the transfer function, differential and integral. The sixth part discusses common-mode-related input and rejection ratios. Parts 7 and 8 look at reference basics.
Subsequent articles will continue exploring various aspects and parameters of the ADC.
About the authors
Sachin Gupta is a Senior Applications Engineer in the Global Applications team at Cypress Semiconductor Corp. He can be reached at sgup@cypress.com .
Akshay Phatak is
an Applications Engineer with Cypress Semiconductor. He holds a
Bachelor's degree in Electronics and Telecommunications form College of
Engineering, Pune (India). He likes to work on mixed-signal embedded
systems. He can be reached at akay@cypress.com.
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