Frontiers in Electronic Testing Analog and Mixed Signal Boundary Scan

Testing of a system does not follow directly from the testing of its parts, and a system built with testable parts can sometimes be impossible to test. Even if all digital chips are compliant with the standard, the testability of a mixed-signal system cannot be guaranteed. The "Mixed-Signal Boundary-Scan Test Bus" is the natural complement to the widely used "Boundary-Scan IEEE Std. 1149.1", commonly known as JTAG. This new mixed-signal standard is called "IEEE Standard 1149.4" and is mainly dedicated to the manufacturing test of analog and mixed-signal boards. But like the IEEE 1149.1 it can be used for many other purposes: the test buses and their digital control form a very general "analog data highway". Increasingly, mixed-signal boards are gaining complexity, making their testing process extremely challenging. At the same time, IC complexity and technology are getting so sophisticated that testing ICs at the board level becomes very expensive. Embedding a part of the board tester on chip is the aim of the IEEE 1149.4. This is a treatment of the design, application and structure of the IEEE 1149.4. It updates the information on digital boundary-scan and addresses chip designers in a dedicated chapter containing guidance to easily build analog circuits including IEEE 1149.4. A basic metrology and a test strategy with the instrumentation needed for it are also described.