A multibit sigma-delta ADC for multimode receivers

A 2.7-V sigma-delta modulator with a 6-bit quantizer is fabricated in a 0.18-/spl mu/m CMOS process. The modulator makes use of noise-shaped dynamic element matching (DEM) and quantizer offset chopping to attain high linearity over a wide bandwidth. The DEM algorithm is implemented in such a way as to minimize additional delay within the feedback loop of the modulator, thereby enabling the use of the highest resolution quantizer yet reported in a multibit sigma-delta analog-to-digital converter of this speed. The part achieves 95-dB peak spurious-free dynamic range and 77-dB signal-to-noise ratio over a 625-kHz bandwidth, and consumes 30 mW at a sampling frequency of 23 MHz. The part achieves 70-dB signal-to-noise ratio over a 1.92-MHz bandwidth and dissipates 50 mW when clocked at 46 MHz.

[1]  W. Sansen,et al.  A high-performance multibit /spl Delta//spl Sigma/ CMOS ADC , 2000, IEEE Journal of Solid-State Circuits.

[2]  Bruce A. Wooley,et al.  A 2.5-V sigma-delta modulator for broadband communications applications , 2001 .

[3]  Ian Galton,et al.  A dynamic element matching technique for reduced-distortion multibit quantization in delta-sigma ADCs , 2001 .

[4]  Joseph Mitola,et al.  Technical challenges in the globalization of software radio , 1999, IEEE Commun. Mag..

[5]  Omid Oliaei Noise analysis of correlated double sampling SC-integrators , 2002, 2002 IEEE International Symposium on Circuits and Systems. Proceedings (Cat. No.02CH37353).

[6]  Ian Galton,et al.  A dynamic element matching technique for reduced-distortion multibit quantization in delta-sigma ADCs , 1999, ISCAS'99. Proceedings of the 1999 IEEE International Symposium on Circuits and Systems VLSI (Cat. No.99CH36349).

[7]  T.S. Fiez,et al.  A 14-bit current-mode /spl Sigma//spl Delta/ DAC based upon rotated data weighted averaging , 2000, IEEE Journal of Solid-State Circuits.