SAMSON2: An Event Driven VLSI Circuit Simulator

This paper describes the circuit simulation algorithms of the SAMSON2 mixed circuit/logic simulator. SAMSON2 employs event driven simulation techniques to exploit the inherent temporal sparseness in VLSI circuits. At the circuit level, SAMSON2 can be more than an order of magnitude faster than a "standard" circuit simulator such as SPICE2 while providing comparable waveform accuracy. This performance is achieved by partitioning a circuit into subcircuits which are allowed to have separate integration step sizes reflecting their activity level. The accuracy of the solution is maintained by controlling the errors due to decoupling among the subnetworks as well as the local truncation within each subnetwork. Simulation examples of typical MOS integrated circuits (IC\´s) are presented. f