An error-controlled methodology for approximate hierarchical symbolic analysis

Limitations of existing approaches for symbolic analysis of large analog circuits are discussed. To address their solution, a new methodology for hierarchical symbolic analysis is introduced. The combination of a hierarchical modeling technique and approximation strategies, comprising circuit reduction, graph-based symbolic solution of circuit equations and matrix-based error control, provides optimum results in terms of speech and quality of results.European Commission ESPRIT 21812Comisión Interministerial de Ciencia y Tecnología TIC97-058

Interpretable Symbolic Small-Signal Characterization of Large Analog Circuits using Determinant Decision Diagrams

: A new approach is proposed to generate interpretable symbolic expressions of small-signal characteristics for large analog circuits. The approach is based on a complete, exact, yet compact representation of symbolic expressions via determinant decision diagrams (DDDs). We show that two key tasks of generating interpretable symbolic expressions --- term de-cancellation and term simplification---can be performed in linear time in terms of the number of DDD vertices. With the number of DDD vertices many-orders-of-magnitude less than the number of product terms, the proposed approach has been shown to be much more efficient than other start-of-the-art approaches. 1. Introduction Mixed-signal (analog and digital) systems are becoming increasingly important. While automation tools exist for digital circuits, analog design is still done manually and depends heavily on designers' experience. In this paper, we present a new approach to generate interpretable analytic expressions for smallsi..