A 113 dB SNR oversampling DAC with segmented noise-shaped scrambling

Consumer formats such as DVD push the performance of audio D/A converters to higher and higher levels. D/A converters with high dynamic range and low cost are now in demand. Previous /spl Sigma//spl Delta/ D/A converters have used 1b digital modulators with switched-capacitor analog filters. The noise of switched-capacitor filters is limited by thermal KT/C noise, so achieving high-dynamic range requires an impractical amount of on-chip capacitance. The design shown differs in several ways from previous /spl Sigma//spl Delta/ D/A converters. A continuous-time output stage avoids the thermal noise added by reasonable-size switched-capacitor circuits. Continuous-time /spl Sigma//spl Delta/ circuits have several serious problems, including high sensitivity to clock jitter, difficulty in filtering the output waveform, and extreme sensitivity to intersymbol interference in the pulse output waveform. These problems are reduced.