Digital Noise-Coupling Technique for Delta-Sigma Modulators With Segmented Quantization

A digital noise-coupling technique for delta-sigma modulators with a high-resolution quantizer is presented. The proposed technique divides the outputs of the quantizer into an MSB segment and an LSB segment. The MSBs are directly fed to the modulator input, whereas the LSBs are used as the quantization noise for noise coupling. After the digital postprocessing, the MSBs and the LSBs are then recombined. As a result, it preserves the benefit of increased quantization levels without suffering from the exponential growth of the dynamic element matching logic. The extra noise shaping introduced by the LSB feedback further reduces the quantization noise leakage caused by the mismatch between the analog and digital noise transfer functions, which allows a more relaxed operational amplifier design. This technique is simple to implement and well suited for low-power and wideband applications.