Testing second-order delta–sigma modulators using pseudo-random patterns

Abstract

Single-bit second-order delta–sigma modulators are commonly used in high-resolution analog-to-digital converters (ADCs). This type of modulator requires high-resolution test stimulus, which is difficult to generate. This paper proposes a novel and robust technique to determine the performance of the modulator by characterizing its key parameters using a pseudo-random pattern sequence. This technique is suitable for BIST application since a pseudo-random sequence can be generated on-chip using LFSR. Numerical simulation results show that this technique is capable of identifying parameters that affect the performance of a second-order delta–sigma modulator ADC.