Computer-aided vulnerability analysis of a digital-to-analog converter

Results are presented on the application of previously developed simplified microcircuit modeling techniques to the analysis of an existing military subsystem in order to identify problem areas and demonstrate the state of the art. The D/A converter subsystem studied is part of the flight instrumentation used in the E4A (military version of 747) aircraft. It contains both digital and analog microcircuits, monolithic and hybrid, as well as discrete bipolar transistors and passive elements. The overall problem approach was that of an engineering vulnerability analysis on the subsystem. The individual components were experimentally characterized and modeled, and the component models were then interconnected to obtain a simulation of the entire D/A converter using an expanded version of the MINI-SCEPTRE computer code. Comparison of computer predictions and experimental data demonstrates reasonably good agreement to within the repeatability of component samples. The major problem is the long computer run time and associated cost for a single photoresponse prediction.