An approach to model-based testing of mixed-signal SiPs

Linear and non-linear Model-based Testing (MbT) has been developed in the past for mixed-signal devices. For Digital- to-Analog Converters (DACs) with a static nonlinear transfer characteristic, linear MbT has even been adopted in production test. The core principle of MbT is to parameterize a model of the on-chip error sources based on the measurements that are performed on the Device Under Test (DUT). The model parameters are then used in order to determine whether the DUT passes or fails the test. Using a linear model reduces the computational effort in applying MbT to multiplying matrices during production test. For non-linear models, the computational effort is larger. In this paper, we report a generalization of MbT applied to combinations of static nonlinearities and dynamic linear systems. The specific example of a DAC followed by a low-pass filter is found, for example, at the boundary between the digital baseband and the RF front-end of a typical transceiver. One technology of integrating the digital baseband and the RF front-end is System-in-Package (SiP). Limited access to internal signals, such as the DAC output in our example, poses particular problems for parameterizing a linear error source model. With our generalization, we provide a reference MbT which allows us to evaluate and compare various linear and non-linear MbT approaches with respect to a specific test application.