A mixed-signal BIST scheme with time-division multiplexing (TDM) comparator and counters

A low-cost and efficient built-in self-test (BIST) scheme is proposed for analog and mixed-signal circuits. We implement the time-division multiplexing (TDM) comparator to analyze the response of a circuit under test (CUT) with minimum hardware overhead. The comparator converts the response to a sequence of ones and zeros by comparing the response to the reference voltages at each time slot using time-division multiplexing. Simple counters are connected to the comparator to accumulate the ones generated at each time slot and used as a signature analyzer. This TDM comparator can be used to monitor internal nodes in addition to the classical primary output nodes to improve circuit testability. Simulation results are presented to illustrate the effectiveness of this scheme.