* Question
How Is the Conversion Accuracy of an A/D Converter Defined?
* Answer
The conversion accuracy of an analog-to-digital converter (ADC) refers to how closely the actual digital output matches the ideal value corresponding to the applied analog input signal.
In an ideal ADC, each input voltage is converted into the exact expected digital code. However, real ADCs may have small deviations caused by factors such as offset error, gain error, integral nonlinearity (INL), differential nonlinearity (DNL), noise, and reference voltage variations.
ADC conversion accuracy is typically expressed as an absolute error or relative error, and is commonly specified in LSB (Least Significant Bit), volts, or a percentage of the full-scale range (%FSR).
When evaluating ADC performance, accuracy should be considered together with other specifications such as resolution, signal-to-noise ratio (SNR), and operating conditions. A higher-resolution ADC does not always provide higher accuracy, as overall measurement performance depends on the complete signal chain.
