An audio ADC Delta-Sigma modulator with 100-dB peak SINAD and 102-dB DR using a second-order mismatch-shaping DAC

E. Fogelman, J. Welz, I. Galton
2001 IEEE Journal of Solid-State Circuits  
A second-order audio analog-to-digital converter (ADC) 16 modulator using a second-order 33-level tree-structured mismatch-shaping digital-to-analog converter (DAC) is presented. Key logic simplifications in the design of the mismatch-shaping DAC encoder are shown which yield the lowest complexity second-order mismatch-shaping DAC known to the authors. The phenomenon of signal-dependent DAC noise modulation in mismatch-shaping DACs is illustrated, and a modified second-order input-layer
more » ... input-layer switching block is presented which reduces inband DAC noise modulation by 6 dB. Implementation details and measured performance of the 3.3-V 0.5-m single-poly CMOS prototype are presented. All 12 prototype devices achieve better than 100-dB signal-to-noise-and-distortion and 102-dB dynamic range over a 10-20 kHz measurement bandwidth. Index Terms-analog-digital conversion, CMOS analog integrated circuits, delta-sigma modulation, digital-analog conversion, dynamic element matching, mixed analog-digital integrated circuits. circuitry and enable the implementation of high-performance ADCs in CMOS fabrication processes optimized for digital circuits [7] . However, realizing these benefits requires an internal digital-to-analog converter (DAC) with linearity and inband noise specifications equal to or better than those of the ADC. The development of mismatch-shaping DACs has helped to address this issue and make the implementation of multibit ADCs practical.
doi:10.1109/4.910472 fatcat:dffh7lxsbzhx7cu4evaci22ske