A simplified polynomial-fitting algorithm for DAC and ADC BIST

Abstract

An accurate and simple method is introduced for determining the third order polynomial that best fits a set of data points containing random noise. The coefficients of the polynomial are translated into offset, gain, and harmonic distortion for an analog-to-digital converter (ADC) driven by a digital-to-analog converter (DAC) or other appropriate signal source. The algorithm is efficient enough to be implemented as a built-in self-test for an IC, and is particularly suitable for sigma-delta converters.