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.