Added ADC Improves Analog Square-Root Extraction Accuracy (.PDF Download)

Known devices for taking the square root contain an operational amplifier and a multiplier connected in a feedback loop. The accuracy of these devices depends on the method of building the multiplier, with the most accurate using logarithm and anti-logarithm functions. However, even these are not accurate to better than ± 0.1% without trimming or calibration. The circuit proposed here removes this limitation associated with the analog multiplier, by using analog-to-digital conversions