A step response based mixed-signal BIST approach

A new mixed-signal built-in self-test approach that is based upon the step response of a reconfigurable (or multifunction) analog block is presented in this paper. The technique requires the overlapping step response of the Circuit Under Test (CUT) for two circuit configurations. Each configuration can be realized by changing the topology of the CUT or by sampling two CUT nodes with differing step responses. The technique can effectively detect both soft and hard faults, and does not require an analog-to-digital converter (ADC) and/or a digital-to-analog converter (DAC). It also does not require any precision voltage sources or comparators. The approach does not require any additional analog circuits to realize the test signal generator and only requires a two input analog multiplexer for CUT output sampling. The paper is concluded with the application of the proposed approach to a ITC´97 analog benchmark circuit