Standardize on common test hardware with a flexible switching matrix

As product complexity continues to increase, test engineers are challenged with improving test coverage on a variety of devices while keeping costs at a minimum. When finished products incorporate hundreds or thousands of devices, developing and maintaining separate test systems for individual components lacks scalability. An approach to this problem is to standardize on a single platform and develop a small number of test systems that can each test tens or hundreds of different devices. Test engineers are increasingly seeing the benefits of developing, deploying, and supporting a reduced number of test systems that use common components. Although many factors such as system assurance and platform longevity influence the long-term success of these systems, the core requirements consist of modular, reconfigurable hardware. A switching matrix is the main hardware component that gives a single test system the flexibility to test a variety of devices. With a switching matrix, you can connect all of your instruments and test points through a series of relays and close relevant relays via software. Switching matrices provide several benefits such as simple connectivity and test repeatability; however, it´s usually not practical to have a switching matrix that completely matches the I/O of your instruments. For example, if you have a 1,000 V DMM, a 2 A power supply, and a 1.5 GHz digitizer, you´re unlikely to find a COTS switching matrix that maximizes those I/O points. Selecting a switching matrix involves evaluating various trade-offs between density, power, bandwidth, and so on and optimizing the cost of your test system. This paper examines the trade-offs you should evaluate when choosing a switching matrix along with considerations for reducing cost and size.