The Modelithics Library incorporates pad scalability into some models, which allows the user to input the desired pad dimensions. To the left, is a graphic showing the three input dimensions for scaling. The limits on the pad input parameters are generally based on the min/max IPC land pattern for the particular component size.
All of the models in the Modelithics CLR Library and the NLD Library can have the pad effects completely disabled. This feature is enabled by setting the Sim_Mode parameter to 2. Under this condition, the reference planes for the models are effectively shifted to the outer edges of the component itself (versus the outer edges of the pad, as is the case when using Sim_Mode = 0).
Any portion of the pads that extends from the outer edges of the component toward the center of the component is also disabled in the model. The intent of this feature is to allow users to separately generate custom pad-effects, e.g. using electromagnetic simulation, and substitute these effects in place of the built-in pad effects that are part of each model. The user should keep in mind that disabling the built-in pad effects is not equivalent to assuming a pad dimension that equals the pad on the component itself; if the goal is to define a mounting pad equal in size to the pad on the component, those pad effects must be added by the user after disabling the built-in pad effects.
The layout geometry for pad-scalable models will now be automatically updated to match user-specified values for the pad dimension parameters. The models can also be placed directly into a layout from the component palette in the layout window. Selecting “Sim_mode = 2” will automatically remove the pad in the layout window and move the connection points to the outer edges of the component body. The NLD Library layout geometry associated with the model requires manual removal or modification of the layout based on the user-defined pad geometry.