Time-resolved emission (TRE) systems are used in many FA labs for internal timing analysis of digital ICs. In this article, the authors explain how they use TRE systems to diagnose analog circuit failures as well. The key to their success is the use of an asynchronous trigger on the emission detector, which eliminates measurement error due to nonlinear distortion. A case study of an analog amplifier failure caused by a polysilicon short demonstrates the effectiveness of their technique.