LibreSolar KiCad schematic symbols library
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LibreSolar schematic symbols library

This library collects all symbols used in the different Libre Solar designs. It should be embedded as a git submodule in a folder called "library" inside the KiCad project directory.

As the Standard KiCad symbols might change without prior notice, all symbols used from the built-in library should be copied into a project specific library or this general Libre Solar library.

Library design rules

The design rules are based on the KiCad Library Convention with some exceptions.

General rules

  • Using a 100mil grid, pin ends and origin must lie on grid nodes.
  • Origin is placed in the middle of symbol.
  • Field text uses a common size of 50mils.
  • The Value field is prefilled with the object name.
  • Description and keywords properties contain the relevant information.
  • For components with a single default footprint, footprint field is filled with valid entry of the format "Footprint_Library:Footprint_Name" and is set to invisible.

Basic symbols

  • The style of basic shematic symbols (resistor, capacitor, diodes, etc.) should follow the IEC 60617-2 standard.

Custom ICs (black-box components)

  • Pins are grouped logically, not necessarily by pin number.
  • Whenever possible, inputs are on the left and outputs are on the right.
  • Power supply pins (GND and VCC) are placed left or right. Top and bottom of the symbol are reserved for name and value:
    • Reference designator centered at the top
    • Component value centered at the bottom

Schematic layout rules

  • In order to be compatible with existing libraries, the grid setup should be set to 100 mils.
  • The overall schematic should be grouped in hierarchical sub-schematics for easier understanding. The default schematic sheet size should be A4.
  • The pins of two devices must always be connected with a wire. It is not allowed to place two devices with their pins together without a wire.
  • The text size should be 50mil for standard text and 100mil for headers.
  • Each component should have the following component property fields:
    • Reference
    • Value
    • Footprint
    • Datasheet (optional)
    • Manufacturer
    • PartNumber
    • Supplier (optional)
    • OrderNumber (optional)
    • Remarks (optional)
  • If the tolerance or voltage of a part is relevant, it should be added in the remarks field and displayed in the schematic.