What Is SAR ADC?

In the modern electronics industry, the Successive Approximation Register (SAR) ADC stands out as an efficient analog-to-digital converter, widely used in applications requiring high precision and rapid response. This article delves into the definition, working principle, characteristics and advantages, and applications of SAR ADCs.

I. What is SAR ADC?

A Successive Approximation Register (SAR) ADC is a type of analog-to-digital converter (ADC) used to convert continuous analog signals into discrete digital signals. Its core feature is the step-by-step approximation method used to achieve accurate digital conversion. SAR ADCs are known for their high precision, fast response, and low power consumption, making them highly effective in various applications.

II. Working Principle

The operation of SAR ADCs relies on a combination of a Successive Approximation Register (SAR) and a Digital-to-Analog Converter (DAC). The basic steps are as follows:

Sampling: The SAR ADC samples the input analog signal and holds it at a stable voltage level.

Comparison: The sampled signal is compared to the reference voltage output by the DAC. The SAR controls this comparison process to determine if the DAC output value is close to the input signal.

Approximation: Based on the comparison results, the SAR gradually adjusts the DAC's output value to approximate the input signal's actual voltage. Each approximation is refined through the comparison process to minimize approximation error.

Output: When the DAC output value closely matches the input signal's voltage, the SAR ADC outputs the final digital value, representing the input signal's voltage.

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