Design verification considering manufacturing tolerances by using worst-case distances

A new method for design verification on circuit level considering the inevitable manufacturing tolerances is presented. It is based on a specific backward evaluation of performance specifications, which can be done efficiently with a sequential quadratic programming method using standard simulation tools. The specific backward evaluation yields exact worst-case parameter sets and corresponding worst-case distances for all specifications separately. Automatic circuit quality analysis enables a detailed design verification and supports the circuit design process by planning aids for a design step. The various features of the method are illustrated using a small tutorial circuit example. A practical example of an integrated CMOS analog circuit proves the efficiency of the new approach