Patent ID: 6937965
Filing Date: 2005-08-30
Classification: G01R

Abstract:
1. A method for determining a specification guardband for a processor used in a system comprising the steps of: a) determining a set of variables representative of system environment, test environment, tester to system offset, and reliability, which affect the specification; b) creating a set of distribution models representative of variables that affect said specification, the set comprising models for the system on which the processor is used; setting up the system environment; modeling system variables distributions during normal operation; setting initial system variables; booting the system at increasing frequencies until the system hangs; running system applications at a highest frequency at which the system functions and record such frequency; changing the initial system variables and performing on new system variables the steps of booting and running applied to the initial system variables; c) creating a distribution model for the system variables representative of the test environment comprising: characterizing electrical and mechanical test system parameters that affect the specification under test; choosing an appropriate distribution model for the test system parameters: d) creating a distribution model representative of tester to system offset comprising: inputting tester to system correlation data; calculating tester to system offset for a set of samples; choosing an appropriate distribution model for the tester to system offset; calculating tester to system mean and sigma based on the sample size; e) creating a reliability wearout distribution model; f) analyzing all the distribution models with a statistical tool that works with the distribution models; and g) selecting a guardband for said specification based on the statistical analysis and a tolerance target for the specification under analysis.