LEF (Library Exchange Format)
Library Exchange Format (LEF) is an open specification for representing physical layout information on components of an integrated circuit in an ASCII format. It represents all required information for a place and route of the components without the need to include the full physical design. It is normally used in conjunction with DEF file format. Besides the component information it also stores some technology information on conducting layers and via layers.
Using LEF in the LayoutEditor
The LEF file format is strong connected with the DEF file format. So both files are needed for a correct display of a physical design. Please first open the corresponding LEF file and then import or attach the DEF file. With the opening of the LEF file also the technology information on routing layers are set. The LayoutEditor is limited in importing LEF files, an export is not possible.
LEF: Handling of layernames
The LEF file format only knows layernames. By opening a LEF file the LayoutEditor analyzed the used layers. If a used layername already exist in the current setup, this layer is used. Otherwise the first unused layer is renamed.
