Transient simulation of lossy interconnect

A new approach for transient simulation of lossy transmission lines terminated in arbitrary nonlinear elements is presented. The approach is based on convolution simulation. By making use of the Pade approximations of each line´s characteristic admittance function and exponential propagation function, the authors derive a recursive convolution formulation, which greatly reduces the computation used to perform convolutions. They analyze the errors introduced by Pade approximations and develop a scheme to determine the necessary order for an approximation. The approach was implemented in the stepwise equivalent conductance MOS timing simulator, SWEC, and, therefore, no Newton-Raphson iteration was needed to simulate lossy lines with nonlinear terminals. The simulation results of SWEC were compared with the results of SPICE3.e; SWEC, which gives accurate results, can be one to two orders-of-magnitude faster