All active IBIS components contains some combination of pullup, pulldown, power clamp, and ground clamp nodes. Power to these nodes can be applied at the component level using the [Pin Mapping], or at the relevant nodes of each pin, using the default power parameters.
Component-Level Power and Ground with Package Models
When you are importing a Single Component with a Package Model, the power and gnd pins that you select are exposed in the schematic to wire to the chosen power or ground rails. Nexxim uses the [Pin Mapping] information (power and ground bus definitions) in the IBIS component definition along with the RLC parasitic data (from die side to board side) in the Package Model definition to connect the power and ground buses to power and ground nodes on the signal pin buffers. The Component External Power property is set to ON in the component. When Component External Power is ON, the power parameters on individual pins is ignored.
The IBIS file may contain a [Pin Mapping] keyword defining buses that connect POWER and GND pins to the voltage supply nodes of any buffers connected to signal pins. When a [Package Model] is used, and the Component External Power is on, Nexxim uses the [Pin Mapping] data to connect the prescribed power buses between the die-side nodes of POWER and GND pins and the voltage supply nodes of buffers. Any imported pins that are NOT included in the Package Model definition use the uncoupled lumped RLC package defined in their [Pin] entry (or [Package] section if no [Pin] RLC data is specified).
Pin-Level Power and Ground
When you are importing either a Single Component without a Package Model, individual pins, or individual buffer models, power connections click the power parameter on the individual pins to control the connections. The power property also controls the power connections when a single component with a [Package Model] has been imported but the Component External Power switch is deactivated; changing the imported POWER and GND pins to No-Connects (NC).
By default, the power parameter is set to internal, so the component automatically drives the nodes using internal voltage sources set to the voltages specified in the IBIS model. When power is set to internal, users should NOT connect any of these nodes to voltage sources or to ground. Connecting external voltage sources or grounds when power is set to internal generates warning messages about parallel supplies, and may cause problems with simulation.
To use external sources and grounds, set the power parameter to external. With this setting, any pull-up, pulldown, power clamp, and ground clamp nodes appear as pin parameters with lists for selecting the external voltage nodes to connect (using page ports).