Linearity testing of ADCs using low linearity stimulus and Kalman filtering

Traditional linearity testing of ADCs involves using a spectrally pure or a highly linear stimulus, along with a large number of samples per code to average out the effects of noise. Test equipments need to house expensive instruments to provide the highly linear stimulus. The large number of samples required for the procedure results in long test times. These two factors are prime contributors to the test cost. In this paper, algorithms which use low linearity stimuli and a Kalman Filter to reduce both the hardware resources and the test time for the test procedure have been proposed. Simulations results for a 14-bit ADC show that a 7-bit linear stimulus with one sample per code can be used to measure the INL of the ADC with a maximum estimation error of 1 LSB.