Translation of specifications in hierarchical analog LSI design

This paper proposes a novel approach for translation of specifications from system level to the next lower level. First, a prescribed response surface model is employed to approximate each output response y(x) over a region of interest /spl Omega/ of a vector of design variables x. The problem is to choose n distinct sampling points x/sub i/ (i=1,...,n) from /spl Omega/ at which observations y(x/sub i/) are to be taken. The data (y(x/sub i/), x/sub i/) are used to determine the parameter values of the response surface model. The derived response surface model and the constraints on the output responses are then transformed into interval-inequality-constrained optimization problem. Interval methods consist a set of procedures for interval arithmetics. They provide solutions for the optimization problem in form of hyperbox space of design variables. This hyperbox is suitable for independent translation of specifications from system level to the next lower level. Our approach successfully applies to analog PLL design.