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ADC Guide, Part 3: offset error

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.

Part 1: the ideal analog/digital converter

Part 2: the sampling rate

Part 3: offset error

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 .

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 .

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1 comment on “ADC Guide, Part 3: offset error

  1. SunitaT
    March 21, 2013

    CDS is also used in CMOS image sensors to remove the fixed pattern
    noise.During the pixel read-out cycle, two samples are taken one when
    the pixel is still in the reset state and the one when the charge has
    been transferred to the read-out node. These two values are then used as differential signals in further stages, such as programmable gain
    amplifiers (PGA) or ADC.

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