Method and apparatus for testing semiconductor devices using an actual board-type product

Semiconductor devices are tested under actual operating conditions by interfacing the devices to an actual board-type product, for example, through a test board tat includes a mounting unit such as a socket or pattern of conductive lands that allows the devices being tested to be mounted to and removed from the test board with minimal effort and signal degradation. An interface circuit on the test board compensates for environmental differences between the board-type product and the mounting unit. For example, the interface circuit can include a clock distribution circuit, which utilizes a phase locked loop, and a register circuit to compensate for electrical loading caused by the device mounting unit, and to provide the proper timing margins between clock signals and control signals applied to the semiconductor devices. A power control circuit can be used to manipulate the supply voltage thereby providing a voltage margin screening function.