A Wide-band 2-path cross-coupled sigma delta ADC

The performance of a sigma-delta ADC can be increased by increasing one or more of the main three parameters, over-sampling ratio, the order of the modulators and the number of bits used. Increasing each of these parameters presents a degree of challenge (i.e., the increase in the over-sampling ratio is limited by the technology and the power consumption requirement). This paper presents a new method to obtain 2^nd order noise shaping from two 1^st order, time interleaved modulators by applying cross-coupling of quantization noise between the two paths. The proposed sigma- delta ADC is implemented in 90 nm CMOS technology.