Design of mixed-signal circuit for testability

The test and design for testability methods for each type of block exist but assume a direct access to the block under test. Thus, an additional design for testability structure using boundary scan and mixed-signal test bus is incorporated for effective test application. With this design, separate specialized tests are applied to analog and digital parts, as well as to interconnects. The area overhead of the test access structure is generally small as it is shown to be inversely proportional to the square root of the block area. While the partitioned architecture provides a reasonable test solution, weakness remains in the test of block interfaces. Delay tests and current measurement tests may provide possible solutions. The problem of testing for systems that use both types of signals is addressed in this paper