Designing nonlinearity characterization for mixed-signal circuits in system-on-chip

Abstract

Long test times and the use of conventional automatic test equipment (ATE) makes conventional mixed-signal linearity performance testing costly. Diminishing test time of linearity test significantly reduces system-on-a-chip production test costs and, therefore, lessens total product manufacturing costs. Several low-cost linearity test methods have addressed this issue for a single-ended mixed-signal circuit testing. On the other hand, a low-cost test approach has rarely been proposed for differential mixed-signal circuits, due to a new class of test obstacles from differential circuits that are widely employed for high-speed I/O products. This paper presents a cost-effective self-test methodology to characterize the linearity performance of differential mixed-signal circuits in loopback mode. The proposed method precisely predicts the device-under-test (DUT) linearity specifications by building accurate DUT nonlinear polynomial models using spectral specifications from recent work. The test cost is significantly reduced by replacing conventional ATE with the proposed self-test platform and by reducing test time to a fraction of conventional testing time. Hardware measurement results validated the test performance of the proposed test scheme.