In semiconductor testing

In semiconductor testing, DUT refers to a specific die on a wafer or the resulting packaged part. Using a connection system, the part is connected to a piece of manual or automatic test equipment. The ATE then applies power to the part, supplies stimulus signals, then measures and evaluates the resulting outputs from the device. In this way, the ATE determines whether the particular device under test is good or bad.

While in the form of a wafer, the ATE connects to the individual DUTs (dice) using a set of microscopic needles. Once the chips are sawn apart and packaged, the ATE connects to the DUTs (packages) using ZIF sockets (sometimes called contactors).

General electronic testing

The term DUT is also used more generally within electronics to refer to any electronic assembly under test. For example, cell phones coming off of an assembly line may be given a final test in the same way as the individual chips were earlier tested. Each cell phone under test is, briefly, the DUT.

The DUT is often connected to the ATE using a bed of nails tester of pogo pins.