Testing in a mixed-signal world

Wide differences in test signals used for analog and digital circuits make a common test for a mixed-signal device difficult. A divide and conquer strategy partitions the circuit into three types of blocks: analog, digital logic and memory. A design for testability structure using boundary scan and analog test bus allows very effective test application. With this design, separate specialized tests are applied to analog and digital parts, as well as to interconnects. While the partitioned architecture provides a reasonable test solution, weakness remains in the test of block interfaces. Research on unified analog-digital tests is recommended. Delay tests and current measurement tests might be possible candidates.