Electronic design automation system and methods utilizing groups of multiple cells having loop-back connections for modeling port electrical characteristics

Abstract

A computer implemented process and system for electronic design automation (EDA) using groups of multiple cells having loop-back connections for modeling port electrical characteristics. Multi-bit cells have multiple gates of the same function implemented within a same cell. Multi-bit components have multiple multi-bit cells implemented within a same component. Scannable multi-bit cells and components are similar to multi-bit cells and components but contain scannable sequential elements with scan chains installed. Multi-bit cells may or may not have each sequential cells' input and each sequential cells' output available externally. The scannable sequential elements of a multi-bit component are ordered into a predefined scan chain which is defined by the library containing the multi-bit component or multi-bit cell. During scan replacement processes of the EDA compile process, multi-bit cells and components of the netlist are replaced with scannable multi-bit cells and components. Also, during optimization, multi-bit cells and components undergo equivalence replacement to meet specified constraints (e.g., area, performance, etc.). To model the electrical characteristics of the port during certain optimizations, loopback connections are applied to the multi-bit components from the scan out port to the scan in port of the multi-bit cell or component, therefore, one loopback connection spans multiple sequential cells within the multi-bit cell or component. During certain optimizations, loopback connections are applied to multiple sequential cells that are coupled together but do not necessarily reside in a multi-bit cell or component. By spanning multiple sequential cells, circuit degeneration is reduced thereby providing better circuit optimizations for netlists having scan circuitry.