Noise Shaping SAR ADCs
In recent years, charge-redistribution SAR (Successive Approximation) ADCs have exhibited the highest conversion efficiencies for ADCs with moderate resolution and bandwidth. For effective resolutions beyond 10 bits or so, however, the accuracy of the SAR circuit blocks limits the converter's overall energy efficiency. For instance, at high resolutions, the DAC voltages become small compared to the input-referred noise of a dynamic comparator, necessitating an additional power-hungry, low-noise pre-amplifier to drive the comparator.
We introduced the noise-shaping SAR ADC architecture to decouple ADC accuracy from both the resolution of the SAR capacitor array and comparator noise. In the short time since its introduction, this pioneering technique has been very widely adopted and forms the basis of some of the world’s most efficient ADCs. In more recent work, we extend noise-shaping SAR speed by interleaving the accuracy through cascaded noise shaping.
L. Jie, B. Zheng, H. W. Chen and M. P. Flynn, “A Cascaded Noise-Shaping SAR Architecture for Robust Order Extension,” IEEE Journal of Solid-State Circuits, December 2020.
L. Jie, B. Zheng and M. P. Flynn, "A Calibration-Free Time-Interleaved Fourth-Order Noise-Shaping SAR ADC," in IEEE Journal of Solid-State Circuits, December 2019.
L. Jie, B. Zheng, H-W. Chen, R. Wang, M. P. Flynn, "A 4th-Order Cascaded-Noise-Shaping SAR ADC with 88dB SNDR Over 100 kHz Bandwidth ," 2020 International Solid-State Circuits Conference, (ISSCC), February 2020.
L. Jie, B. Zheng and M. P. Flynn, "20.3 A 50MHz-Bandwidth 70.4dB-SNDR Calibration-Free Time-Interleaved 4th-Order Noise-Shaping SAR ADC," 2019 IEEE International Solid- State Circuits Conference, (ISSCC), February 2019.
J.A. Fredenburg and M. P. Flynn, "A 90-MS/s 11-MHz-Bandwidth 62-dB SNDR Noise-Shaping SAR ADC," IEEE Journal of Solid-State Circuits, December 2012.
J. Fredenburg, and M. P. Flynn, "A 90MS/s 11MHz Bandwidth 62dB SNDR Noise-shaping SAR ADC," (ISSCC) IEEE International Solid-State Circuits Conference, San Francisco, CA, pp. 468-469, February, 2012.
L. Jie, B. Zheng and M. P. Flynn, "A Calibration-Free Time-Interleaved Fourth-Order Noise-Shaping SAR ADC," in IEEE Journal of Solid-State Circuits, December 2019.
L. Jie, B. Zheng, H-W. Chen, R. Wang, M. P. Flynn, "A 4th-Order Cascaded-Noise-Shaping SAR ADC with 88dB SNDR Over 100 kHz Bandwidth ," 2020 International Solid-State Circuits Conference, (ISSCC), February 2020.
L. Jie, B. Zheng and M. P. Flynn, "20.3 A 50MHz-Bandwidth 70.4dB-SNDR Calibration-Free Time-Interleaved 4th-Order Noise-Shaping SAR ADC," 2019 IEEE International Solid- State Circuits Conference, (ISSCC), February 2019.
J.A. Fredenburg and M. P. Flynn, "A 90-MS/s 11-MHz-Bandwidth 62-dB SNDR Noise-Shaping SAR ADC," IEEE Journal of Solid-State Circuits, December 2012.
J. Fredenburg, and M. P. Flynn, "A 90MS/s 11MHz Bandwidth 62dB SNDR Noise-shaping SAR ADC," (ISSCC) IEEE International Solid-State Circuits Conference, San Francisco, CA, pp. 468-469, February, 2012.