Break the kT over C Noise Limit Slides

Abstract: The sampling kT over C noise is traditionally deemed as a fundamental SNR limit for Nyquist-rate ADCs. To suppress it, the only option is to increase C. Nevertheless, this leads to significant challenges for the ADC input driver and the reference buffer. In fact, the ADC driver and reference buffer are the system bottleneck nowadays. Their power, area, and design complexity can be an order of magnitude higher than the ADC core. Since the root cause of this challenge is the large C, it is highly desirable to break this seemingly fundamental tradeoff between the capacitor size and the kT over C noise. This talk will introduce two techniques that can significantly reduce the capacitor size but without incurring large kT over C noise penalty. The first technique is to operate a SAR ADC in the continuous time to completely avoid the need for the sampling operation. The second is to cancel the kT over C noise using a novel two-step sampling operation. Both techniques can achieve high resolution with orders of magnitude reduction in the capacitance size, thereby substantially relaxing the requirement for the ADC input driver and reference buffer.

Speaker Biography: Nan Sun is Professor with Tsinghua University since 2020. He was Assistant and then tenured Associate Professor with University of Texas at Austin. He received B.S. degree from Tsinghua University in 2006, and Ph.D. degree from Harvard University in 2010. Dr. Sun received the NSF Career Award in 2013, and the IEEE SSCS New Frontier Award in 2020. He has published 30+ JSSC papers and 50+ ISSCC, VLSI, CICC, ESSCIRC papers. He has graduated 24 PhD students, 10 of whom are professors at top universities in the US and China. He serves on the Technical Program Committee of CICC and ASSCC. He was Associate Editor of TCAS-I, and a Guest Editor of JSSC. He also serves as Distinguished Lecturer for both IEEE Circuits-and-Systems Society and IEEE Solid-State Circuits Society.