Programming Active Load

Programmable Levels

The pin state for the current cycle dynamically controls the active load. You can program the active load with the following pin levels using the NI-Digital Pattern Driver or set pin levels interactively in the Digital Pattern Editor. These levels apply only when the termination mode is set to active load, the specified pins are in a non-drive pin state (L, H, X, V, M), and the selected pin function is Digital. Pin levels are programmable per pin or by pin group.

I_OL—Specifies the current that the DUT sinks from the active load while outputting a voltage below V_COM.

I_OH—Specifies the current that the DUT sources to the active load while outputting a voltage above V_COM.

V_COM—Specifies the commutating voltage level at which the active load circuit switches between sourcing current and sinking current.

You can use the active load to provide pull-up or pull-down functionality for an open-drain DUT, such as in an I2C interface. When the DUT drives low, the DUT sinks current sourced by the active load. When the DUT stops driving low, the active load of the digital pattern instrument continues sourcing current until the voltage on the pin reaches V_COM.