Tradeoff analysis for producing high quality tests for custom circuits in PowerPC/sup TM/ microprocessors

Custom circuits, in contrast to those synthesized by automatic tools, are manually designed blocks of which performance is critical to the full chip operation. Testing these block represents a major challenge and hence, a crucial time-to-market factor in micro-processor design flow. This paper investigates various methodologies for testing custom blocks. Issues of efficiently obtaining proper circuit model for ATPG tools as well as producing quality tests are analyzed and discussed. Tradeoffs among various methods are analyzed and compared. Experience and results based on recent PowerPC microprocessors will be reported.