Yahui Ji, Chenye Zhang, Hao Gu, School of Integrated Circuits, Tsinghua University, China; Peiran Zhang, Department of Electronic Engineering, Tsinghua University, China; Jianle Liu, School of Integrated Circuits, Tsinghua University, China; Fan Yang, Department of Electronic Engineering, Tsinghua University, China; Tianxiang Nan, School of Integrated Circuits, Tsinghua University, China