Diagnosing integrator leakage of single-bit first-order ΔΣ modulator using DC input

Integrator leakage is a dominant factor in the SNR (signal-to-noise ratio) loss of DeltaSigma modulators. In this paper, we propose a design-for-test (DfT) technique to diagnose the integrator leakage of the single-bit first-order DeltaSigma modulator. The proposed technique is a low-cost solution; it only adds two multiplexers to the modulator, utilizes a single DC voltage as the test stimulus, and estimates the integrator leakage by analyzing the digitized bit stream. Furthermore, the technique can be easily extended to higher order DeltaSigma modulators. Simulation results show that accurate estimations of the integrator leakage can be achieved even at the presence of noise.