Design of NCL Gates with the ASCEnD Flow

Silicon technologies advances brought the possibility of integrating billions of transistors in a die. However, as transistors get smaller, some of the aspects that were negligible in previous technologies emerge as difficulties for the design in current and future technology nodes. In this context, fully synchronous circuits are harder to be built, as timing closure constraints become difficult to be met, and the asynchronous paradigm gains interest in the research community for its ability to cope with current technologies issues. ASCEnD was proposed as a standard cell library for supporting standard-cell based design of asynchronous circuits and comprises a design flow for asynchronous components. This work presents the use of the ASCEnD flow to design NCL gates, which enable design improvement opportunities for some asynchronous templates. A total of 14 different NCL gates were designed at the layout level and had their electrical behavior characterized. As a result, electrical and physical models of these gates are now part of the ASCEnD library.