Test Strategies for Embedded ADC Cores in a System-on-Chip, A Case Study

Testing of a deeply embedded mixed-signal core in a System-on-Chip (SoC) is a challenging issue due to the communication bottleneck in accessing the core from external automatic test equipment. Consequently, in many cases the preferred approach is built-in self-test (BIST), where the major part of test activity is performed within the unit-under-test and only final results are communicated to the external tester. IEEE Standard 1500 provides efficient test infrastructure for testing digital cores however, its applications in mixed-signal core test remain an open issue. In this paper we address the problem of implementing BIST of a mixed-signal core in a IEEE Std 1500 test wrapper and discuss advantages and drawbacks of different test strategies. While the case study is focused on histogram based test of ADC, test strategies of other types of mixed-signal cores related to trade-off between performance (i.e., test time) and required resources are likely to follow similar conclusions.