Hi, I've started collecting a few ideas on use cases for the new component format. I suspect others have done the same.
Is there a good place to collect all of these and/or collaboratively edit them? Simon
# KiCad Schematic Components: Use Cases This document tries to capture the use cases for the upcoming redesign of schematic component handling in KiCad. ## Standard Components - standard components have distinctive symbols - different national and international standards might specify different symbols for the same component - users prefer different symbol sizes - components typically but not necessarily have a value (resistance, capacitance, inductance) - component values may be part numbers (e.g. diodes) - components might have additional values that may be relevant for the circuit in question (e.g. power rating, bandwidth) but often can be ignored (e.g. power rating in voltage dividers) - additional values may derive from the primary value (e.g. diode part number defines forward voltage), but need not - active components have power sources, but users might not want to annotate these for every instance - logic gates have no common representation of their power source for historical reasons - multiple standard components might be packed together into a single package (e.g. quad op-amps) - for multi-unit packages, power supply pins can be shared between units or groups of units - units in multi-unit packages may be exchangeable, even between different packages - constraints may apply to unit swapping (e.g. using the same power supply) - pins on the same unit may be swappable (e.g. AND/OR/XOR gates) - the same component may be available in different packages, with different pinouts ## Connectors - the electrical properties of connectors are dependent on the application and cannot be generalized in the component definition - standardized connectors exist with fixed mappings - some connectors have multiple different mappings (e.g. miniPCIe/mSATA) - when two interconnecting boards are designed, they require opposite connector definitions ## Integrated Circuits - ICs are typically represented as boxes with labeled pins - users might prefer to generate this representation from a table rather than paint it by hand. - ICs can have hundreds or thousands of pins, which makes the symbol unwieldly to use; users might prefer to create subunits - IC pins may be exchangeable, subject to constraints - it may be desirable to delay pin assignment until routing if multiple options exist - IC pins may be organized in banks sharing a common power supply or reference voltage - the same IC may be available in different packages, with different pinouts (e.g. TQFP and BGA variants) - ICs may be very similar between variants (e.g. different voltages); users might want to reuse information between them - pins may be configurable for different functions, subject to constraints ## Special-purpose ICs - users may prefer to use hand-drawn symbols even for ICs (e.g. a package containing protection diodes may represent them visually) ## ERC - component pins of active components are usually referenced to supply pins - connected components should usually, but not always be connected to the same supply rails - component pin type may be dependent on chip configuration ## Part Selection - part filtering may depend on supplementary values (e.g. resistor package depends on power rating) - single- and multi-unit parts might be candidates for components - unused units might need termination (e.g. op-amps) ## SPICE - schema components can be mapped to SPICE components for simulation - depending on the component type, the value needs to be translated in different ways (e.g. diodes are referenced by type, with forward voltage as fallback, while resistors just use the value)
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