The next step toward completing the product design is to enter the schematic details into a computer-based schematic capture program once a natural philosophy style engineer has completed their application circuit design.
An electronic design automation (EDA) or computer-controlled design (PCB CAD) software package’s schematic capture program can generate a list from the finished schematic that outlines each electrical connection between each electronic component.
When developing a printed circuit board using EDA or PCB CAD software, the computer circuit board or PCB designer uses this internet list. The physical assembly and interconnection platform for the various electronic components required by the schematic can be provided by the finished printed circuit board.
The printed circuit board is made up of one or more layers of insulant, like epoxy-filled fiberglass, that separate the semiconducting copper layers and provide the board with mechanical strength. The semiconducting copper plating is used to make the component pads and interconnection traces.
Parts would be on the highest side of a one-layer board, and connecting traces would be on the rock bottom. There are two possible configurations for a double-layer board: it may only have components on the top side, or it may have components on both the top and bottom sides, as well as connecting traces on each side. There would be components and traces on both the top and bottom sides of a multilayer board, as well as a number of internal layers used for interconnections, voltage, and ground plane layers.
Ad powered. In addition, a series of knowledge files for each semiconducting layer—top, bottom, and any internal layers—provide comprehensive information about the finished board design to the PCB CAD or EDA program. The standard format for these data files is the Gerber File format, after the pioneering photoplotter manufacturer Gerber Scientific Instruments Company.
The initial Gerber format followed the EIA RS-274D standard and included a tool description file and command files for each conductive layer. A photoplotter might be equipped with the knowledge necessary to create a graphic representation thanks to the command file’s collection of brief commands, each of which was followed by a collection of X and Y coordinates. The Gerber files were given to these command files. The dimensional information and trace line widths for each pad and geometric shape on the layer were outlined in the tool description file, or aperture file.
The computer-generated data files for the computer circuit board design are then sent to a printed circuit board fabrication company for production of the actual boards. The Gerber files contain all of the information that is required for the computer-controlled machines at PCB fabrication facilities to print the copper layers for the element pads and association traces, drill all of the required holes, and cut the board to the desired size.
The older Gerber format EIA RS-274D always assumed a group of command files, one for each PCB layer and one tool description file, or aperture file, since a PCB could have one to several semiconducting layers. Since there was no standard for aperture files, each EDA or PCB CAD product had its own version of the format. The aperture data would need to be manually re-entered in the event that the computer circuit board fabrication facility was unable to scan the aperture file format as it was sent.
The aperture information is embedded in the file headers of every command or Gerber file in the more recent Gerber format, which conforms to EIA RS-274X. Typically, this more recent format is referred to as X-Gerber. Each X-Gerber file contains all of the information required to fabricate the connected portion of a PCB layer because all of the aperture information is enclosed between the header and the file.
Field-grade officerr the Gerber files should have names that are sufficiently descriptive for the PCB storyteller to understand the board and board layer to which each file applies, such as membdtop.gbr. The quality method is to include a unique readme.txt file with each set of files for a board design that describes each file name and its use in the design. This readme.txt file can serve as the starting point for the board production process for the marketer.
The most common Gerber file extensions are.GBR,.GBX, or.ART. Instead of the.GB_ type extensions, extensions like.TOP,.BOT, or.SMT,.SMB are typically used. The EDA or PCB CAD software usually controls the file extension for a particular type of file—top, bottom, silkscreen, paste, or inner layer—or allows for selection within the package. Because of this variation in the extensions, the board vendor must include the readme.txt file in the entire file package.
For a double-sided, two-layer PCB, the Gerber files will accommodate two positive Gerber layers, top and bottom; aperture file, if not within the RS-274X format; Tar Heel State Excellon drill file; Drill Tool List file; Silkscreen file for every facet with components; soldermask files for high and bottom; and top and bottom screen paste files for surface mount boards whenever applicable. All of these files and two files for the inner layer would be on a board with four layers, while all of these files and four files for the inner layer would be on a board with six layers.
