MassMind : Applications : CAD : PWB CAD : OrCAD

OrCAD Tutorial by Vikas Shukla of ReferenceDesigner.com

Board Layout Introduction

This tutorial is intended for beginners in printed circuit board design who wish to complete a board using Layout Tool. This Tutorial should work on version 10.2 or 10.5 and some higher and some lower versions.

INTRODUCTION

Those who have had experience with one or more PCB design tools may wish to skip this page. Others may like to get a general view of the design process which is as follows:

1. Select the components (capacitors, sockets, etc.) you will be using on your board. Once you have a list, collect the datasheets and look at the suggested footprints (that is, the hole sizes, pads size and position, etc...) in those documents.

The main categories of the components used are:

Resistors, Capacitors,Inductors, Ferrite Beads
Diodes, Transistors, FETS, LEDs
Connectors, Headers
ICs, BGA ICs
Others

Interestingly, you must be very careful about the electrically simplest component - connectors. You must get the physical part in hand to verify pin number 1 orientation and dimensions.

2. For each component, you have to create a footprint. The footprint is a physical view of the component that includes the holes through your board or pads for surface mount components. Footprints can be reused in the same board several times.

In practise, you will already have most of the footprints available and you should need to create only few additional footprints for a new design. You will need to be careful to verify that the existing footprint in your design library matches the mechanical dimension of the component according to its datasheet.

You may use some of the designs and the footprints that are already there. As the time passes you will have database of more and more components and you should be able to reuse these.

3. You have to create a schematic view of your board. This means adding different components on your Schematics capture tool and connecting them with wires. We will be creating Schematics using Orcad. If you are not familiar with Orcad Schematics you may want to review an Orcad Schematics tutorial.

4. Once you have the schematic, you have to generate the netlist and import it to OrCAD Layout Editor to start the board layout. You place the components, define power and ground planes, and route physical wires using this tool. Finally you must verify the board for errors.

5. After you have the board layout, you generate a few files called artwork or gerbers. The gerber files are used by PCB Manufacturers to make the board.

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