Analyzing and addressing the impact of test fixture relays for multi-gigabit ATE I/O characterization applications

Relays are some of the most frequently used components on test fixtures for automated test applications. With data-rates of current I/O interfaces already reaching 5 Gbps and beyond in desktop applications and expected to continue to increase, test engineers must make the decision to continue using relays on the high-speed signal lines, or remove the relays from the test fixture signal paths and sacrifice the flexibility they provide. This paper presents some results and guidelines on using relays in test fixtures for 10 Gbps applications. A commercially available relay was selected and integrated into a typical ATE test fixture design. Special consideration was given to the footprint optimization through 3D-EM simulation and the use of passive equalization to compensate for some of the relay losses. The paper concludes with measurements of an experimental test fixture using an ATE system running 10 Gbps.