版图与电路图网表.pptVIP

版图与电路图网表的比较 layout versus schematic（LVS) Getting Started with LVS LVS stands for layout versus schematic. This netlist comparison tool compares two netlists to determine whether they describe the same circuit. When they do not, LVS works in conjunction with L-Edit to identify and correct errors. LVS can be used to determine whether a schematic circuit matches a layout, or whether two different schematics or layouts implement the same circuit. LVS has the following features: SPICE input format LVS accepts standard SPICE-format netlists, such as those produced by NetTran and L-Edit. Fragmentation identification When two netlists are not equivalent, LVS can identify unresolvable nodes and devices and assist in locating them on the original schematic or layout. Automorphism resolution LVS identifies automorph classes—sets of elements or nodes (such as devices in parallel) which cannot be distinguished from one another. To resolve automorph classes, LVS can either employ user-supplied prematch information or a detailed trial matching process. Parameter comparison LVS uses topological (device types, number of connections), parametric (resistance, capacitance), and geometric (area, length, width) information to compare netlists. Matching thresholds can be defined to specify how different two values can be while still comparing equivalently. Different margins can be defined forparametric and geometric comparisons. Permuted class resolution LVS can identify the switching of two elements in series. Launching LVS You can launch LVS by one of five methods: Clicking the Start button on the Windows toolbar and navigating to the application through the Programs menu Double-clicking the LVS icon on your desktop Double-clicking an LVS verification database (.vdb) file in Windows Explorer Double-clicking an LVS batch (.bat) file in Windows Explorer Invoking LVS from a DOS command prompt Input and Output Files LVS requires two SPICE-format