Steps For Making A Pcb

Procedure for creating a PCB:

OrCAD Capture:

* First to create a PCB circuit, we start by opening OrCAD Capture ("File", "New" and click on "Design" or "Project.

* Afterwards, we click the "Place Part" submenu and we add the important and necessary libraries. If necessary we place the parts and make correct connections (it is done by typing the name of the part we want in "Part" and choosing "Part Search" so that we can click on "Begin Search" and choose any library files that are necessary for our project).

* Then we place the respected parts and link them depending on the schematic given.

* Afterwards, we place "No Connect" for any unconnected pins.

* It is recommended to click on "No Connect" for any useless pins (according to the circuit) in order to facilitate the schematic's design.

* We have to be sure that all part have a unique "Part Reference" and if applicable, a "Value" so that the circuit will be error-free.

* After the circuit is completed, we click on "DRC check" in order to prevent any errors that are present. And if there is any, we correct them before proceeding (to produce a DRC check, we should go into the project's main menu and select the DRC check button under the "Tool" menu).

* Afterwards, we should add a footprint to all the necessary components by editing or modifying a component and adding a footprint in the "PCB Footprint" column (a footprint is basically the "blueprint" of the circuit, in other words, its unique combination will help choose the best possible parts in order to design a perfect circuit. To find the PCB Footprint for a specific part, the "Library Footprints" book is located in almost every CDST computer lab.

* Annotating the design by making sure that "Update entire Design" and "Unconditional Reference Part" are checked.

* Then we should create a "Netlist" (.MNL) file by going to the "Create Netlist" option, "Layout" sub-option and checking that "Combined property string:" has "{PCB Footprint}" also that "Run ECO to Layout" is NOT selected.

Layout:

* First we open OrCAD Layout ("File", "New" in order to load a "_Default" template file so that we look and load our .MNL file. In this case, the "_Default.tch"file is needed to building the circuit.

* Afterwards, we pick a name for our .MAX file (this is where our layout design will be stored),

* Then we "Link" our components to a correct footprint (in Capture, this procedure is already done but if Layout finds that an incorrect PCB footprint was used, then it will automatically help the user find the correct footprint for the respected parts.

* The moment our layout appears: we click on the "Component" button and place the parts in order to prevent that the lines cross. If line crossing is inevitable, then 2 or more layers must be used.

* In order to add a new component, we click the right mouse button (we're still in "Component" mode), and click on "New" and then we pick the correct footprint and place the new part.

* Afterwards, we add mounting holes by utilizing the "MTHOLE1" footprint.

* We then click on the Shove" mode (Then we trace or draw by clicking in the yellow wires or lines. Generally, the IC wiring must be on the bottom as it is simpler to solder. We switch to the top layer using a "Free Via" if the lines must cross).

* If we want to erase a trace (we're still in "Shove" mode), we put a pointer over the line and pressing "Del" on the keyboard.

* If we want to put a connection, we click on the "Connection" mode button and put our new connection.

* If we want to delete a connection, we right click (we're still in "Connection" mode) and pick "delete" and select our line.

* If we want to add or delete any text on the circuit, we click on the "Text" mode button. To erase text, we place the mouse pointer over the text and press "Del". If we want to add text we just have to right click and select "New".

* Afterwards, we draw a "Border Outline" by clicking on the "Obstacle" icon then we trace our border (Note that the yellow line must never touch the circuit or the parts of the circuit or else it will be deleted by the Border Outline).

* Then we place our Drill chart by selection the "tools" menu, then "Drill Chart" and "Move". Then we place our chart (It is recommended to reduce the size of the Drill Chart by going into its properties so that it will fit if we want to print the circuit alongside the Drill Chart together.

* If we want to print the circuit, layers can be made visible or invisible (setting the ratio to 2 for 1 is recommended.

* Afterwards, we go to "Tools", "Net", "Select from Spreadsheet". Changing the values to Min=15, Con=20, Max=20 (by double-clicking the "Width" column) is best suited to drill the board.

* It is important to set the circuit's properties to "Millimeter" instead of "Mills" (by going to "Options", "System Settings") so that the circuit will be correctly drilled.

* Then we click on "Tools", "Padstack" and "Select from Spreadsheet" so that we can find and change the "DRILL" and "DRLDWG" section (for every part) to set the pad width to "0.8" and the "TOP" and "BOTTOM" (for every part also) to "1.80" so that the circuit will be properly drilled and designed.

* Afterwards, we run "Post Processor" by going to the "Auto" menu to get the Gerber files. It is important that we have the .TOP, .BOT, .GND, and .TAP for the Circuit Cam program.