SAR-Assisted Pipeline ADCs and Ring Amplifiers
Portable electronic applications, including wireless communication, imaging, and video, demand high-resolution (≥12b) analog-to-digital conversion with signal bandwidths of tens of MHz. Our work in 2010 introduced the SAR assisted pipeline ADC to revolutionize the efficiency and performance of the pipeline ADCs. More recently we have harnessed ring-amplifiers to deliver record efficiency from the SAR-assisted-pipeline ADC architecture.
The pipeline ADC architecture is famous because of its high resolution and high speed. However, pipeline ADCs depend on good component matching and require high-gain and high-bandwidth op-amps for good performance. In contrast, straightforward analog content makes the SAR architecture well suited to nanometer CMOS processes, but SAR ADCs are limited in speed due to their serial decision-making process. Furthermore, comparator noise and limited capacitor matching limit the practical resolution of SAR ADCs. In the SAR-assisted pipeline, we combine the SAR and pipeline architectures to deliver performance and efficiency.
The pipeline ADC architecture is famous because of its high resolution and high speed. However, pipeline ADCs depend on good component matching and require high-gain and high-bandwidth op-amps for good performance. In contrast, straightforward analog content makes the SAR architecture well suited to nanometer CMOS processes, but SAR ADCs are limited in speed due to their serial decision-making process. Furthermore, comparator noise and limited capacitor matching limit the practical resolution of SAR ADCs. In the SAR-assisted pipeline, we combine the SAR and pipeline architectures to deliver performance and efficiency.
The ring-amplifier, introduced by UnKu Moon’s group at Oregon State University, is an energy-efficient replacement for the conventional op-amp. Our work combines ring amplifiers with the SAR-assisted pipeline ADC. We simplify the biasing of the ring-amplifier to make it more practical. We also increase the ring-amplifier gain to make it compelling for high-resolution ADCs.
Y. Lim and M.P. Flynn, “A Calibration-free 2.3 mW 73.2 dB SNDR 15b 100 MS/s Four-Stage Fully Differential Ring Amplifier Based SAR-Assisted Pipeline ADC” 2017 IEEE Symposium on VLSI Circuits.
Y. Lim and M.P. Flynn, "A 1 mW 71.5 dB SNDR 50 MS/s 13 bit Fully Differential Ring Amplifier Based SAR-Assisted Pipeline ADC," IEEE Journal of Solid State Circuits, December 2015.
Yong Lim, M. P. Flynn, "A 1mW 71.5dB SNDR 50MS/S 13b fully differential ring-amplifier-based SAR-assisted pipeline ADC," Solid- State Circuits Conference - (ISSCC), IEEE International, 2015.
Y. Lim and M.P. Flynn, " A 100 MS/s, 10.5 Bit, 2.46 mW Comparator-Less Pipeline ADC Using Self-Biased Ring Amplifiers," IEEE Journal of Solid State Circuits, October 2015.
C. C. Lee and M. P. Flynn, “A SAR Assisted 2-Stage Pipeline ADC,” IEEE Journal of Solid-State Circuits, April 2011
C. Lee and M. P. Flynn, “A 12b 50MS/s 3.5mW SAR Assisted 2-Stage Pipeline ADC,” IEEE Symposium on VLSI Circuits, June 2010
Y. Lim and M.P. Flynn, "A 1 mW 71.5 dB SNDR 50 MS/s 13 bit Fully Differential Ring Amplifier Based SAR-Assisted Pipeline ADC," IEEE Journal of Solid State Circuits, December 2015.
Yong Lim, M. P. Flynn, "A 1mW 71.5dB SNDR 50MS/S 13b fully differential ring-amplifier-based SAR-assisted pipeline ADC," Solid- State Circuits Conference - (ISSCC), IEEE International, 2015.
Y. Lim and M.P. Flynn, " A 100 MS/s, 10.5 Bit, 2.46 mW Comparator-Less Pipeline ADC Using Self-Biased Ring Amplifiers," IEEE Journal of Solid State Circuits, October 2015.
C. C. Lee and M. P. Flynn, “A SAR Assisted 2-Stage Pipeline ADC,” IEEE Journal of Solid-State Circuits, April 2011
C. Lee and M. P. Flynn, “A 12b 50MS/s 3.5mW SAR Assisted 2-Stage Pipeline ADC,” IEEE Symposium on VLSI Circuits, June 2010