ACOBs: A DFT technique for analog circuits

Analog circuit observer blocks (ACOBs), a design for test technique for analog and mixed signal integrated circuits, are on-chip structures designed to reduce the need for high precision in measuring analog signals during circuit test. A comprehensive analysis of duplication-based on chip checking, particularly on the impact of small parametric deviations in the various analog components due to normal process variations, demonstrate that trade offs has to be made almost always in designing the testing scheme. Applied to single-ended and fully differential circuits and to a data converter, ACOBs utilizing data duplication with little or zero hardware duplication effectively targets spot defect, as well as process variations induced faults.