Distinguishing process variation induced faults from manufacturing defects in analog circuits using V-transform coefficients

Parametric fault distinction between those arising from process variation as opposed to manufacturing defects in components of an analog integrated circuit is presented. Such a fault distinction has significance in the correction and calibration of process steps responsible for manufacturing defects, thereby improving manufacturing yield. In this paper, we begin by laying out foundations for high sensitivity analog circuit test from our previous work on analog circuit test based on V-transform coefficients. Next, we present the Bayesian fault classification of parametric faults arising from process variation against manufacturing defects. Our experiments are based on a benchmark fifth order elliptic filter. We use SPICE program for fault injection, with about 50,000 Monte Carlo simulation runs to demonstrate fault detection-diagnosis under process variation. The test scheme uncovers 95% of all injected single parametric faults whose sizes deviate 5% from the nominal values of circuit components corrected for process variation, while the procedure successfully diagnosed all component faults under ±3σ process variation with 88% confidence level.