Symbolic simulation of analog circuits in S- and Z-domain

A new symbolic simulator, called ISAAC, (interactive symbolic analysis of analog circuits), is described. ISAAC can derive all AC characteristics of both time-continuous and time-discrete analog circuits. Any linear network function is calculated by means of the consecutive setup and resolution of a set of s- or z-domain compacted MNA (CMNA) equations. Symbolic term cancellations are treated in an efficient way. ISAAC can generate both exact and compact approximated results. The approximation is performed by means of a heuristic algorithm. For complex cells such as a Miller compensated opamp and a fifth-order SC ladder filter, CPU times on a one MIPS machine are below 30 s.<<ETX>>