An Essentially Non-Oscillatory (ENO) high-order accurate Adaptive table model for device modeling

Abstract

Modern analytical device models become more and more complicated and expensive to evaluate in circuit simulation. Interpolation based table look-up device models become increasingly important for fast circuit simulation. Traditional table model trades accuracy for speed and is only used in fast-Spice simulators but not good enough for prime-time Spice simulators such as SPECTRE. We propose a novel table model technology that uses high-order essentially non-oscillatory (ENO) polynomial interpolation in multi-dimensions to guarantee smoothness in multi-dimensions and high accuracy in approximating i -- v/q --v curves. An efficient transfinite blending technique for the reconstruction of multi-dimensional tables is used. Interpolation stencil is adaptively determined by automatic accuracy control. The method has been proved to be superior to traditional ones and successfully applied in Spectre and Ultrasim for simulating digital, analog, RF, and mixed-signal circuits.