Patent ID: 7996737
Filing Date: 2011-08-09
Classification: H01L

Abstract:
1. A method of uniquely identifying instantiations of functionally equivalent circuits comprising: expressing small manufacturing tolerance related-differences between particular instantiations of the functionally equivalent circuits in terms of a plurality of multi-bit numbers, each multi-bit number being associated with a particular gate or a group of gates of an instantiation of said functionally equivalent circuits; determining said multi-bit numbers for a particular instantiation of said functionally equivalent circuits, said multi-bit numbers serving to uniquely identify said particular instantiation of said functionally equivalent circuits from other instantiations of said functionally equivalent circuits; storing the multi-bit numbers for said particular instantiation of said functionally equivalent circuits; installing said particular instantiation of said functionally equivalent circuits in an item of equipment; and testing said item of equipment for a presence of said particular instantiation of said functionally equivalent circuits in said item of equipment by determining said multi-bit numbers for the particular instantiation of said functionally equivalent circuits in said item of equipment and comparing the results of said determination of said multi-bit numbers with the stored multi-bit numbers corresponding to the particular instantiation of said functionally equivalent circuits originally installed in said item of equipment.