Feasibility regions and their significance to the hierarchical optimization of analog and mixed-signal systems

Physical effects have to be considered throughout the design of analog integrated circuits. The difficulties in modeling these effects at higher levels of abstraction is a major obstacle for a top-down analog design that proceeds from high to low levels of abstraction. This paper discusses a hierarchical top-down design style with feasibility regions as a means to describe physical effects at different levels of abstraction. We suggest a method to calculate linearized approximations to the feasibility regions at higher levels based on Fourier-Motzkin elimination.