SPICE (Simulation Program with Integrated Circuit Emphasis) has become an indispensable tool for the simulation of transistor-level circuits since its introduction in the early 1970s [1]. Over the years, many SPICE simulators have been introduced and their capabilities have been greatly improved. However, as we move into deeper sub-micron designs and circuit sizes keep increasing, the capabilities of current SPICE simulators prove insufficient; continuous performance breakthroughs are needed to keep up with the demands of larger circuits, high accuracy and fast turn-around. SPICE developers have put lots of effort to improve speed. In this paper, we will present how GPU is used to accelerate SPICE simulation with 10 × + performance gain.

In this paper, we propose an efficient oscillation-diminishing cubic Hermite spline interpolation method for the table-based transistor model approximation. We use the cubic Hermite spline interpolation to ensure the continuity of the derivatives. Oscillation-diminishing techniques are proposed to reduce the oscillations (bumps) of interpolations such that both convergence and accuracy are significantly improved. Further, the oscillation-diminishing schemes do not rely on any real derivatives. Therefore, the proposed method can be used to build table models from measured data of the physical devices, where the real derivatives are not always available. In the proposed method, an adaptive approach is employed to generate the nonuniform interpolation grids such that the interpolation accuracy is guaranteed and the memory requirement is minimized. We also propose a novel combined exponential extrapolation method for off-state (leakage) current, which exactly follows the exponential-decay characteristic of that current. Test simulations on several classic industrial analog and mixed-signal circuits show that the proposed method can achieve high accuracy with lower computational cost compared with existing table-based model approximation methods.