EC-24.1 From Schematic to Netlist: Capture, Symbols and Choosing Parts

Work through these

• A schematic drawn to be reviewed: sheets, hierarchy and net naming

  Signal flowing left to right, supplies at the top, one function per sheet and named nets rather than long wires are conventions that make a drawing readable by somebody else. A schematic nobody can review is not finished.

  NPTEL: Electronic Systems Design — Circuits and PCB Design with CAD Software (IIT Delhi) · Course

• Symbol and footprint: the two halves of a library part, and the gap between them

  The symbol is what you draw with and the footprint is what gets etched, and they are connected only by the pin numbering you entered. Checking that mapping against the data sheet drawing catches the most expensive class of mistake.

  NPTEL: Electronic Systems Design — Circuits and PCB Design with CAD Software (IIT Delhi) · Course

• The netlist as the contract between schematic and layout

  Everything the layout tool knows about connectivity comes from the netlist, so a mistake in the schematic is faithfully manufactured. Reading the netlist directly is a fast way to check a small board.

• Choosing parts: availability, lifetime notices and second sources

  A component with one supplier and a long lead time is a risk to the whole product, whatever its specification. Checking stock and lifecycle status is part of selection rather than a purchasing afterthought.

• The bill of materials, and what it must contain to be orderable

  A reference designator, a quantity, a manufacturer part number and a description are the minimum somebody needs to buy the right parts. A list of values without part numbers guarantees the wrong components arrive.

  NPTEL: An Introduction to Electronics Systems Packaging (IISc Bangalore) · Course

• Design rule checking on the schematic, before anything is laid out

  Unconnected pins, outputs driving outputs and missing supplies are caught by a check that takes seconds. Running it before layout saves a revision that would otherwise be found on a manufactured board.