Architectures for multi-bit oversampled A/D converter employing dynamic element matching techniques

A novel class of dynamic element matching techniques is applied to multibit Sigma - Delta A/D (analog-to-digital) converters. The approach translates the harmonic distortion components of a non-ideal DAC (digital-to-analog converter) in the feedback loop of the Sigma - Delta A/D converter to high-frequency components, which can then be filtered out by the decimation filter. Extensive computer simulations have confirmed that a third-order Sigma - Delta A/D converter using a 3-bit quantizer and the new dynamic element matching internal DAC can achieve 104 dB (17+bit) dynamic range and a harmonic distortion below 100 dB with an oversampling ratio of only 64. A chip has been designed in 1.2 mu m CMOS technology.<
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