Background Theory > Schematic Design > Schematic Virtual Parts

In the context of electronic design, a "schematic virtual part" typically refers to a representation of a component in a schematic diagram that does not correspond to a physical electronic component. Instead, it serves as a placeholder or a virtual representation of a part that will be defined later or has external dependencies.

Schematic virtual parts are used in various scenarios, including:

•Future Component Selection: When designing a circuit, there may be instances where the exact component specifications are not yet determined, or the availability of the specific component is uncertain. In such cases, designers can use a virtual part as a placeholder until they finalize the component selection.

•Custom Components: In some designs, custom-made or specialized components may be used, which do not have pre-defined schematic symbols or models in the library. Designers can create virtual parts with custom names and attributes to represent these components in the schematic.

•External Components: In complex systems, certain components might reside outside the schematic or even outside the entire design project. Virtual parts allow designers to represent connections or signals to external components while keeping the main schematic organized and concise.

•Simulation Models: Some components may require complex behavioral or SPICE simulation models that are not readily available in the standard library. Virtual parts can be used to represent these components while the actual simulation models are created or obtained from external sources.

•Documentation and Annotations: Virtual parts can also be used to annotate the schematic with additional information or to indicate specific design requirements, without introducing unnecessary clutter to the diagram.

When using schematic virtual parts, it's crucial to ensure that they are properly documented, and their purpose is clearly communicated with other team members or collaborators. They should be replaced with actual physical components or complete simulation models before finalizing the design or proceeding to the PCB layout phase.

DEX supports virtual parts and allow designers to define custom symbols or placeholders with specific attributes to represent components that will be completed or finalized later in the design process.