Generating, capturing and processing supply current signatures from analogue macros in mixed-signal ASICs

Transient Response Testing is a powerful test technique for analogue macros in mixed-signal electronic systems which with some enhancement can be particularly useful for testing deeply buried circuit structures. Supply current testing is finding widespread application in the digital domain and its use in the analogue domain may lead to integrated test methodologies for mixed-signal systems. This paper shows that by utilizing both these techniques, and a low-cost test shell, deeply buried analogue macros can be partitioned, tested using Transient Response Testing and the resulting response accurately captured from the total device supply current. It also contains an analysis of the noise on the supply current, due to digital circuit activity during testing, and demonstrates a test response analysis technique which is insensitive to it.