TOLERANCE SYNTHESIS BASED ON SENSITIVITY ANALYSIS

Abstract

The tolerance allocation for passive discrete elements of analog devices is an important task when planning mass serial production. Permissible deviations from rated values affects on the cost, the choice of preferred number series for parameters and the acquisition availability of these components. The element tolerances, as well as the temperature dependence and aging effects, are the key factors affecting the product performances and the yield. The solution of this problem has received attention in the scientific and technical literature for more than 40 years. During this time, the tools for designing electronic devices have changed. Computer-aided design (CAD) systems for electronics - Electronic Design Automation (EDA) have become widely used, providing an end-to-end design flow. Modern EDAs have limited capabilities for tolerance design, providing a solution to the problem of tolerance analysis. EDA users have to determine element tolerances based on their intuition and experience through time-consuming interactive optimization. Using specialized tolerance software tools without integration with professional grade EDA is not an acceptable solution. The purpose of the study is to substantiate decisions for the tolerance synthesis in the end-to-end design flow in the EDA environment. The article discusses methods for determining tolerances using the results of sensitivity analysis. Sensitivities can be obtained using standard EDA tools. The implementation of these methods in the Excel environment is considered. To exchange data between the spreadsheet and the EDA schematic databases is proposed to use the clipboard. The proposed solutions make it possible to reduce the number of interactive operations and time spent when tolerance allocation. An example of analog device tolerance design in the EDA environment is given.