Self-positioning digital window comparators for mixed-signal DfT

digital part. Recently a simple comparator scheme has been The use of simple digital window comparators for the onpresented in detail. Based on digital gates in different chip evaluation ofanalogue signals is described. II is shown that configurations, a so-called digital window comparator [6, 101 can a window can be created by choosing different gate input he realised. This, paper deals with the implementation of the configurations. The potentialproblem of lot-to-lot variation of dieital window comoarator. the adiustment of the window and a the comuarator window oosition can be comuensated bv an onI chip repositioning technique. The components for the implementation comprise of a reference comparator and the evaluation comparators that are described along with the implementation of the technique. It is shown, that this technique allows the automatic lot condition adjustment for the evaluation comparator windows. The technique can optionally provide lot condition diagnostics for the test record as well as diagnosis of the actual window selection of the evaluation comparator.