Self-testing of fully differential multistage circuits using common-mode excitation

A fault-oriented testing of fully differential multistage circuits is investigated. The non-concurrent method is proposed, which employs the common-mode excitation of the circuit under test (CUT). Two variants of the method are considered. The first one utilizes natural inputs of each differential stage for the excitation and requires separation of stages during testing, the second one uses an extra input pin of op-amps and performs testing of multistage circuits without partitioning them into separate blocks. The contribution of this paper is the theoretical and experimental validation of the method. It is shown that the method is superior, in test quality, over the previously reported one that exploits the differential-mode excitation. The comparison is performed on the basis of test quality metrics estimated with parts per million (ppm) accuracy. To accurately calculate the test metrics: defect level, yield loss and fault coverage, a probabilistic model of performances of the CUT is derived. It is used in a probabilistic framework for evaluating the test metrics associated with manufacturing tolerances and uncertainty in a comparator threshold. The method is applied to a stagger-tuned band-pass Deliyannis-Friend filter. Work is supported by measurements in the board-level built-in self-tester (BIST) that validate the deterministic capabilities of the method and statistical experiments that validate probabilistic features. (C) 2008 Elsevier Ltd. All rights reserved.