Challenges and solutions for multi-Gigahertz testing

There are several approaches that can be applied to the multi-Gigahertz testing problem. These can be classified as either (1) internal test, as in built-in self test (BIST), or (2) external test, as applied by automated test equipment (ATE). Both these general strategies are in widespread use today. Furthermore, they are often used together to solve particularly challenging test requirements. Since the BIST and ATE approaches each have their benefits and limitations, the combination of the two provides for a variety of trade-offs. However, another degree of freedom is represented by the introduction of active circuitry near to the DUT (typically mounted on the load board). This we refer to as a "test support processor" (TSP). Generally the approach may involve the use of BIST and ATE as well as the TSP itself.