OpenSAR: An Open Source Automated End-to-end SAR ADC Compiler

Abstract

Despite recent developments in automated analog sizing and analog layout generation, there is doubt whether analog design automation techniques could scale to system-level designs. On the other hand, analog designs are considered major roadblocks for open source hardware with limited available design automation tools. In this work, we present OpenSAR, the first open source automated end-to-end successive approximation register (SAR) analog-to-digital converter (ADC) compiler. OpenSAR only requires system performance specifications as the minimal input and outputs DRC and LVS clean layouts. Compared with prior work, we leverage automated placement and routing to generate analog building blocks, removing the need to design layout templates or libraries. We optimize the redundant non-binary capacitor digital-to-analog converter (CDAC) array design for yield considerations with a template-based layout generator that interleaves capacitor rows and columns to reduce process gradient mismatch. Post layout simulations demonstrate that the generated prototype designs achieve state-of-the-art resolution, speed, and energy efficiency.