Mixed Signal Built-In Self-Test for Analog Circuits

摘要

A Built-In Self-Test architecture was developed for testing analog circuits in mixed-signal systems. The Built-In Self-Test circuitry primarily resides in the digital portion of the mixed-signal system in order to minimize performance impact on the analog circuitry. The test pattern generation portion of the Built-In Self-Test circuitry produces a number of different test waveforms found to be effective in detecting faults in the analog circuitry. The output response analysis function consists of a double-precision accumulator that facilitates determination of the faulty/fault-free status of an analog circuit with acceptable component parameter variations. Ten benchmark circuits were established for the evaluation of analog testing approaches along with acceptable component parameter variations and a standard set of faults and fault models for each benchmark circuit. Finally, an equation was developed for the calculation of analog fault coverage that takes into consideration the probability of potential detection of faults due to component parameter variation. Evaluation of the Built-In Self-Test architecture via analog fault simulation using the benchmark circuits and the fault coverage equation indicates that the approach is effective in detecting catastrophe and parametric faults in a wide variety of analog circuits.