Low-cost test of embedded RF/analog/mixed-signal circuits in SOPs

Increasing levels of integration and high speeds of operation have made the problem of testing complex systems-on-packages (SOPs) very difficult. Testing packages with multigigahertz RF and optical components is even more difficult as external tester costs tend to escalate rapidly beyond 3 GHz. The extent of the problem can be gauged by the fact that test cost is approaching almost 40% of the total manufacturing cost of these packages. To alleviate test costs, various solutions relying on built-off test (BOT) and built-in test (BIT) of embedded high-speed components of SOPs have been developed. These migrate some of the external tester functions to the tester load board (BOT) and to the package and the die encapsulated in the package (BIT) in an "intelligent" manner. This paper provides a discussion of the emerging BOT and BIT schemes for embedded high-speed RF/analog/mixed-signal circuits in SOPs. The pros and cons of each scheme are discussed and preliminary available data on case studies are presented.