Circuit Simulation for Mixedsigna Analog/digital Circuits Analog/digital Circuits Circuit Simulation for Mixed-signal Analogldigital Circuits

The increasing use of mixed signal circuits with analog and digital circuitry on the same lchip have created a set of demands that traditional circuit simuiators cannot meet very well. We pmsent techniques to efficiently handle the simulation of mixed signal analog/digital circuits, a d SYMPHONY , a fast mixed-signal simulator which embodies them. SYMPHONY combines a fast simulator for digital circuits with a traditional nonlinear slolver a la SPICE for the analog subcircuits. The digital simulator uses Stepwise Equivalence Conductance to model nonlinear device conductances and Piecewise Linear voltage waveforms. Device kharacter-istics of bipolar elements in digital subcircuits are modeled by a Piecewise Linear apprbximation using the Extended Chebyshev Points, such that the worst case approximation error is @himized. Dynamic circuit partitioning is used to fully exploit the latency and multirate behavior Of the circuit. The simulator is implemented in an event-driven framework with local and global docks for even management. A set of benchmark results are presented on a suit of BiMOS circuits, A transistor level power estimator which exploits algorithms for fast circuit simulation to compute the power dissipation of CMOS circuits is also presented. The proposed approach use$ stepwise equivalent conductance and piecewise linear wavefom approximation. The power estitnator has been implemented in the SWEC framework. Experimental results indicate that SWEC obtain a substantial speed-up over HSPICE (and handle circuits that HSPICE cannot) while maintaining an accuracy of within 5-78. Benchmark results on a suite of industry circuits are presented,