A multi-level cascaded delta-sigma modulator with reduced quantization noise leakage

A cascaded delta-sigma modulator has been proposed that converts analog signals to multi-level digital outputs. The shaped quantization noise generated in the first-stage modulator is transferred to the cascaded stage, efficiently suppressing quantization noise leakage due to analog circuit imperfections. Our model analysis and behavioral simulation confirmed that even if the opamp gain is finite, the signal-to-noise ratio (SNR) is higher than that of conventional noise-canceling architecture.