Chapter 15 - Analog and Mixed-Signal Test Architectures

Abstract

Although analog integrated circuits (ICs) and the analog portion of mixed-signal ICs consist of fewer components compared to their digital counterparts, testing analog and mixed-signal devices is more complex regardless of whether the testing approach is specification oriented or defect oriented. This chapter presents some of the important distinctions between these two approaches and some of the fundamental tests that are applied to analog circuits. In addition, it focuses on some representative built-in self-test (BIST) techniques that have been developed for both functional and structural testing that can be incorporated in mixed-signal IC and SOC implementations to test analog modules. Because the incorporation of BIST circuitry incurs area and associated cost penalties, there are many applications, such as low-cost consumer electronics, in which it may not be worthwhile to consider BIST. On the other hand, high-reliability applications, such as space and medical electronics, are excellent candidates for the incorporation of BIST techniques. The implementation and operation of the BIST approaches presented in this chapter provide insight into many of the issues that must also be considered for more traditional, non-BIST approaches to analog testing. DSP and FFT-based approaches provide a wealth of test and measurement capabilities and form the core of spectrum analyzers, which, in turn, are a key component of external testing. For SOC implementations, incorporation of an FFT can be costly in terms of area, particularly for high-resolution frequency discrimination. However, when incorporated in an SOC for DSP system applications, not only can the FFT be used for output response analysis, but it can also be extended to test pattern generation during functional testing.