The Application of IDDX Test Strategies in Analogue and Mixed Signal IC’s

Supply Current Testing (IDDQ) has become an important defect oriented test strategy for digital IC products. The technique takes advantage of the low quiescent supply current drawn by static CMOS circuits relative to the current consumption during state changes. However, in analogue and mixed signal IC’s this condition can rarely be observed, as in most circuits, steady state currents depend on the biasing conditions and the circuit design. This paper reviews analogue current monitoring proposals, investigates some of the problems related to the use of these techniques and attempts to categorise a number of analogue design styles against the probable suitability for current testing methodologies.