LSI circuit simulation on vector computers

The simulation of Large-Scale-Integrated (LSI) circuits requires very long run times on conventional circuit analysis programs such as SPICE2. A new simulator for LSI circuits, CLASSIE, has been developed which is more efficient and preserves the same accuracy. Two basic factors of present technology are considered in the design of the new LSI circuit simulator. First, LSI circuits are usually a collection of a limited number of structurally identical functional blocks such as logic gates, operational amplifiers, etc. The second is the availability of vector computers which provide an ideal architecture for fast computations on repetitive structures. SPICE2 operates on an entire circuit matrix which is processed at the individual electrical element level. The analysis in the new program takes into consideration the structure of the LSI circuit. The identical functional blocks are grouped together and the simulation is performed at two levels. The above design considerations speed up the simulation of an LSI circuit performed by CLASSIE considerably compared to SPICE2. For the analysis of a large circuit, CLASSIE on a vector computer rates in simulation speed between SPICE2 and a timing simulator. For various test circuits containing from a few hundred to a few thousand semiconductor devices, CLASSIE simulation runs on a CRAY-1 indicate that the speedup compared to SPICE2 increases with circuit size. The solution techniques implemented in the new simulator make the execution time grow linearly with increasing circuit complexity in comparison to an exponential growth in a conventional circuit simulator. Vectorized device-model evaluation and a machine-code solver using both vector and scalar operations bring about the increased performance