ACKNOWLEDGEMENT

First of all I would like to thank to my teachers who guided me whenever I faced

problems during my training. In my six months industrial training it is a wonderful

experience to be a part of EUREKA ELECTROSOFT PVT. LMTED where I have

opportunity to work under brilliant minds. I owe my deep regards for the supporting

and kind staff authorities who are helping me in my lean patches during this course.

The knowledge I am gaining throughout my studies have the practical implementation

during this period. I am grateful to all the staff of EEAST and for their timely support

and sharing of their experience with me. I would like to express my heartiest concern

for Ms . Baljot kaur for her able guidance and for her inspiring attitude, praiseworthy

attitude and honest support. Not to forget the pain staking efforts of our college training

and placement cell and specially my training and placement officer. Last but not the

least I would express my utmost regards for the electronics and communication

department of my Institute.

34

COMPANY PROFILE

EUREKA ELECTROSOFT SOLUTIONS PVT. LTD (EESPL)

……..making IT happen

Augmentation is a dream virtue of every performer – we at EESPL envisaged on a

theme for providing a new epitome of IT solutions in the embedded Telecom &

Software based Product development services. Our edge right from the start was

creating a perceptible differentiation among the plethora of communized IT solutions.

EESPL - where progress is a winning habit

Eureka ElectroSoft Solutions Pvt. Ltd. (EESPL) is primarily operating as a

registered R & D lab for the development and conception of Advanced Automation

related software and hardware solutions. Our expertise includes electronics and

software based stand alone solutions as well as combined integrated solutions termed as

“Electrosoft Solutions”. At EESPL over the years we have developed a core

competency to maximize the quality & innovation parameter while working on

any task. Our proven values have made us as a prime leader in providing

customized solutions.

It is our stiff endeavor to amplify our clients viewpoints and to carve up their

thoughts. This in turn is transformed into factual scenario working models with a

collection of prime technological aspects. All this is and much more in the shortest

turnaround period.

EESPL – the background and essence of operations

The year 2002 witnessed the birth of a visualization – which was to impart economy

with a pinnacle swiftness of innovation in contemporary Industrial IT Solutions. There

came EESPL and a new chapter of imparting excellence in IT techniques came into

subsistence.

34

That was the foundation and today the road voyaged by EESPL encompasses years of

reliance, accomplishments and above all unlimited bonds. Bonds that speak for

themselves, relationships that reflect factual progress. Triumph at EESPL is defined as

the never ending smile on our dear customer’s face. At EESPL we do not impart

conception, we create endearing teams.

Indulging within minds, Imparting technologies

Understanding the pulsation of a customer forms our principal challenge. Assurances

that mean results, efforts that capitulate advancement and outcomes that move

imaginings form the spirit of our day after day working. Timeliness is of chief value to

us and understanding the modern day race for time, we deliver the maximum in

minimum and that too with precision.

Our approach of operation also constitutes of a dedicated Registered Research and

Development lab to make available the final deliverables with thread bare technologies.

Our precedence is often devised on the scale of our customer’s desires. After carefully

analyzing on the need based approach we craft a well planned set of operations – each

fragment is build with an in depth focus on customer’s requirements.

34

CONTENTS

PCB designing

Types of PCB

Techniques used for PCB designing

Orcad design environment

Starting capture

Project manager

Session log

Layout

Design window

Power system design

Bibliography

PCB DESIGNING34

PCB stands for “PRINTED CIRCUIT BOARD”. Printed circuit board (PCB) provides

both the physical structure for mounting and holding the components as well as the

electrical interconnection between the components. That means a PCB = PWB (printed

wiring board) is the platform upon which electronic components such as integrated

circuit chips and other components are mounted. A PCB consists of a non-conducting

substrate (typically fiber glass with epoxy as resin) upon which the conductive pattern

or circuitry is formed. Copper is the most prevalent conductor although nickel, silver

and tin are also used in some cases.

Types of PCB

PCB may be of different types:-

1) Single-sided

2) Double-sided

3) Multilayer

Single sided PCBs: - As the name suggest in these designs the conductive pattern is

only at in one side. And also the size is large in these case but these are cheap.

Double sided PCBs: - These are the PCBs on which the conductive pattern is in on

both sides. The size of board is small in this case but it is costlier than that of above.

Multilayer PCBs: - In this case the board consists of alternating layers of conducting

pattern and insulating material. The conductive material is connected across the layers

through plated through holes. The size of this PCB is smaller than that of double sided

PCB but it is very costly.

PCBs may also be either rigid, flexible, or the combination of two (rigid-flex). When

the electronic components have been mounted on the PCB, the combination of PCB

and components is an electronic assembly, also called PRINTED CIRCUIT

ASSEMBLY. This assembly is the basic building block for all the electronic appliances

such as television, computer and other goods.

FUNCTIONS OF PCB

34

Printed circuited boards are dielectric substrates with metallic circuitry formed on that.

They are some times referred to as the base line in electronic packaging. Electronic

packaging is fundamentally an inter connection technology and the PCB is the baseline

building block of this technology.

TECHNIQUES USED FOR PCB DESIGNING

There mainly two techniques which are use for the PCB designs.

1. Hand Taping

2. Computer Aided Design

1) PCBs using Hand Taping:

o PCB design using hand taping is the process of technical

drawing.

o In hand taping method layout should be prepared on grid paper.

o In hand taping, components pads can be prepared by using black

pads.

o Routing of the board can be done by tapes with different widths.

Each layer (top, bottom) has to prepare separately.

DISADVANTAGS OF HAND-TAPING FOR PCB DESINING:

Each layer has to be designed sep

We cannot generate NCD files for CNC drilling.

Difficult to modify the design in the designing process or after designing.

2) PCB DESIGNING USING CAD

All the above difficulties can be removed by using CAB system.

34

CAD system for PCB designing requires following:

o A computer system.

o PCB design software like OrCad, CADSTAR, Protel, TANGO,

Mentor etc.

o A photo plotter for art work generation.

There are many enhanced features in electronics design automation tools which not

possible in the hand taping. The main advantages are given below:

o Auto placement

o Auto routing

o After routing, optimization of tracks can be done.

o Provides physical design reuse modules

o Electrical rule check (ERC)

o All the layers are generated from the same design by giving different

options.

o Bill of material can be generated which contains number of different

components used.

o We can draw conductors as an arc, semi-circular at different angles.

o Design Rule Check

o Advanced CAD systems have high speed analysis.

o CAD system provides all NCD files and Gerber data files for photo

plotting.

BASIC DESIGN STEPS IN CAD- SYSTEM

The following design steps are very common while designing a PCD in CAD:

Entry the schematic diagram.

Net list file creation.

Placement of components manually or automatically.

Routing of the board using manual routing tools or auto router

Design rule check physical and electrical.

Artwork generation.

34

OrCad Design Environment

OrCad has a long history of providing individuals and teams with a complete set of

technologies that offer unprecedented productivity, seamless tool integration, and

exceptional value. New 10.5 release continues that tradition.Today's lower cost and yet

highly sophisticated electronic design automation systems have created a unique

challenge to nearly every engineering department. Therefore the use of EDA tools has

become increasingly important as product lifecycles have become shorter and shorter.

Modern electronic design automation (EDA) tools are beginning to support a more

efficient and integrated approach to electronic.OrCad Capture® design entry is the most

widely used schematic entry system in electronic design today for one simple reason:

fast and universal design entry. Whether you're designing a new analog circuit, revising

schematic diagram for an existing PCB, or designing a digital block diagram with an

HDL module, OrCad Capture provides simple schematic commands you need to enter,

modify and verify the design for PCB. OrCad Layout ® offers PCB designers and PCB

design teams the power and flexibility to create and share PCB data and constraints

across the design flow. OrCad Layout delivers all the capabilities to designers need

from netlist to place and route, to final output. The ease-of use and intuitive capabilities

of OrCad Layout

PCB DESIGN STEPS IN OrCad 9.1

Entry of Schematic Diagram

Schematic diagram provides the functional flow and the graphical representation of an

electronic circuit. The entry of schematic diagram is the first step in PCB design using

OrCad.

A schematic diagram consists of:-

Electrical connections(nets)

Junctions

Integrated circuits symbols

Discrete components symbols like resistors, capacitors etc.

34

Input / output connectors

Power and ground symbols

Buses

No connection symbols

Components reference names

Text

The Schematic Page Editor:

The schematic page editor is used to display and edit schematic pages. So that one can

parts; wires; buses and draw graphics. The schematic page editor has a tool palette that

we can use to draw and place everything we need to create a schematic page. One can

print from within the schematic page editor, or from the project window.

34

Starting Capture

The OrCAD Release 9 installation process puts Capture in the \PROGRAM FILES\ORCAD\CAPTURE folder, and adds “OrCAD Release 9” to the Programs menu (available from the Start button).

To start Capture

From the Start menu, choose Programs. The Programs menu displays.From the OrCAD Release 9 menu item, choose Capture.

The Capture session frame

Once we start Capture, we see the Capture session frame we do all your schematic design and processing within this window.The minimized Session Log icon in the lower left portion of the Capture session frame is the session log. The session log provides information about everything we have done in the current Capture session. Detailed information about this window—and the other windows in Capture.

34

The Capture work environment

In Capture, each design that we open is in a separate project manager window. If we need to work simultaneously with several designs, we can open them all, and each will have its own project manager window. Depending on which type of window we have active(an active window is one whose title bar is highlighted), certain buttons on the toolbar and certain items on the menus may be unavailable, since we perform tasks and use tools based upon the type of window that is active. Also, the menus and menu choices vary, depending on which type of window is active. The available menus and menu choices will also vary depending upon the type of project you are working with.

It shows the windows we see in Capture: the project manager, the schematic page see in Capture: the project manager, the schematic page editor, the part editor, the text editor, and the session log. It also introduces we to the toolbar, tool palettes, and general Capture concepts such as selecting and editing objects, editing properties, and undoing and repeating actions.

The project manager

we use the project manager to collect and organize all the resources we need for our project. These resources include schematic folders, schematic pages, part libraries, parts, VHDL files, and output reports such as bills of materials and netlists. A project doesn’t actually contain all the resources. It merely “points to” the various files that the project uses.For this reason, we don’t move or delete any files referenced by a project. If we do, the project won’t be able to find them. The project file is saved with an .OPJ file extension. It is an ASCII file, and can be viewed in any text editor.

Project manager folders

34

34

The project manager provides a graphical display of a project’s resources by grouping them into appropriate folders. Design Resources folder is the design folder with the design’s schematic folders and schematic pages, and a Design Cache folder that shows all the parts used on the schematic pages. Any schematic folders or schematic pages that we create are automatically added to the design folder (in Fig. the design folder is named DESIGN3.DSN). we can also add other files or information using the Project command on the Edit menu

The Library folder (in the Design Resources folder) shows the schematic part library files we’ve added to the project using the Project command on the Edit menu.The Outputs folder shows the output of Capture’s processing tools. Generally, these files include bill of materials reports and technology-specific netlists Capture adds the appropriate files to this folder as each is created.

Each project may have only one design, but may have multiple libraries. The design may consist of any number of schematics or VHDL models, but it must have a single root moduleThe root module is defined as the top level of the design. That is, all other modules in the design are referenced within the root module.

Within the project manager, we can expand or collapse the structure we see by double-clicking on a folder, or by clicking on the plus sign or minus sign to the left of a folder. A plus sign indicates that the folder has contents that are not currently visible; a minus sign indicates that the folder is open and its contents are visible, listed below the folder. It appears as a schematic folder with a slash on it in a design file, or as a page in a VHDL file.

Each project we open has its own project manager window. we can move or copy folders or files between projects by dragging them from one project manager window to another (as well as to and from Windows Explorer). To copy rather than move items, press and hold the C key while we drag them. If we close a project manager window, we close the project.

34

In the project manager’s File tab, double-clicking on a schematic folder expands it and displays icons for each schematic page within the schematic folder. Then, if we double-click on a schematic page icon, the schematic page opens in a schematic page editor. Or, if the page is already open, its window becomes active.

A design can consist of a single schematic page within a single schematic folder, or a number of schematic pages within a number of schematic folders. A schematic folder“contains” schematic pages in a relationship similar to the relationship between a directory and the files it contains. Files are contained in a directory; schematic pages are contained in a schematic folder.

34

34

A schematic page provides a graphical description of the electrical connectivity of a design. It is made up of parts, wires, and other electrical symbols. A schematic page may also contain borders, title blocks, text, and graphics. Capture acts on any schematic folders or schematic pages we have selected within an active project manager window.

For example, the Find and Browse commands on the project manager’s Edit menu, the Print command on the project manager’s File menu, and the various tools on the Tools menu, only apply to the selected schematic folder or page.

Project manager tabs—File and Hierarchy

The project manager provides two ways to display a project’s resources. If we choose the File tab, the project manager displays all the project’s folders, schematic folders, and schematic pages. These are displayed in a tree-like fashion. we can expand or collapse the tree by clicking the plus sign in front of the icon. When that branch of the tree is expanded, the plus sign change to a minus sign.If we choose the Hierarchy tab, the project manager displays the hierarchical relationship among the project’s schematic folders and schematic pages.

Single view

34

34

Versions of Capture prior to Release 9 used logical mode and physical mode to separate instance and occurrence information. Now, both instances and occurrences are contained in a single view. The project manager shows all occurrences in the Hierarchy tab.In versions of Capture prior to Release 9, it was necessary to switch modes before creating a netlist for use with OrCAD Layout. Now, the netlist tool provides an option to use either the instance properties or the occurrence properties for creating a netlist.

The schematic page editor

The schematic page editor is used to display and edit schematic pages. we can place parts, wires, buses, and draw graphics. The schematic page editor has a tool palette that we can use to draw and place everything we need to create a schematic page. we can print from within the schematic page editor, or from the project manager window.

Schematic page editor

34

The part editor

The part editor is used to create and edit parts.

From the View menu of the part editor you can choose either Part or Package. In Part view we can:

Create and edit parts and symbols, then store them in new or existing libraries. Create and edit power and ground symbols, off-page connector symbols, and

title blocks. Use the tool palette’s electrical tools to place pins on parts, and its drawing tools

to draw parts and symbols.

34

Package view shows the entire package. A package is a physical part that contains more than one logical part. we can edit the properties of the entire package, such as part reference, prefix, part alias, and so on. we cannot edit individual parts in this view, but we can select individual parts to edit by double-clicking on them.

The part editor is very similar to the symbol editor. The main difference between the two is the symbol editor’s lack of Pin and Pin

Array tool palette buttons.

The session log

The session log lists the events that have occurred during the current Capture session, including messages resulting from using Capture’s tools. To display

34

context-sensitive help for an error message, put the cursor in the error message line in the session log and press The ruler along the top appears in either inches or millimeters, depending on which measurement system (U.S. or Metric) is selected in the Windows Control Panel. we can add tab settings to the ruler by clicking in the ruler bar, dragging the tabs to different positions, or remove them by dragging them down into the session log window. our tab settings are saved and used each time we start Capture.

we can search for information in the session log using the Find command on the Edit menu. We can also save the contents of the session log to a file, which is

useful when working with OrCAD’s technical support staff to solve technical problems. The default filename is SESSION.TXT.

To display the session log

Click on the session log’s maximize button, or choose Session Log from the Window menu.

To minimize the session log

Click the minimize button on the title bar.

To copy session log text to the Clipboard

Select the session log window to make it active.Select the text and choose Copy from the Edit menu.

To print the session log

Select the session log window to make it active.From the File menu, choose the Print command.

To use Find in the session log

34

Select the session log window to make it active.

34

From the Edit menu, choose the Find command. The Find dialog box appears.Enter the word or words that we want to find.Click Find Next.

To save the session log to a text file

Select the session log window to make it active.From the File menu, choose the Save As command. The Save As dialog box appears.Enter a file name in the File name text box. By default, the session log is saved to SESSION.TXT in the current directory. If necessary, specify a new location for the file.

Click Save. The session log text is saved to the file.

The toolbar

The toolbar is always docked on the top edge of the session frame the first timewe open a project in a new session frame of Capture. The position of the tool palette is not saved.Capture’s toolbar is dockable(that is, we can select an area between buttons and drag the toolbar to a new location) and resizable, and displays tooltips for each tool. By choosing a tool button, we can quickly perform a task. If a tool button is dimmed,we can’t perform that task in the current situation.

34

The part editor tool palette

The first group of tools on the part editor tool palette are electrical tools, used to place pins and IEEE symbols. The second group of tools are drawing tools, used to create graphical objects without electrical connectivity

34

Starting a project

A project file (.OPJ) stores pointers to a single design file(.DSN), and can also contain libraries, VHDL files, and output reports associated with the design file. A design file contains one or more schematic folders, in which there are one or more schematic pages. A design file also contains a design cache,which is like an embedded library- it contains a copy of all the parts and symbols used on the schematic pages. When a design is saved with the project file, information from the various Tools dialog boxes is also saved in the project file.

Creating new projects,designs, libraries

we can create a new project, and then create new designs, libraries.

To create a new project

From the File menu, choose New, then choose Project. The New Project dialog

box appears.

Type a name for our new project in the Name text box

Use the Browse button to select a new directory.

Select a project type in the Create a New Project Using group box, and click OK.

Capture provides the following project types:

Analog or mixed signal circuit—select this type of project if we intend to use your

design with OrCAD PSpice. Follow the guidance of the Analog Mixed-Mode Project

wizard to add the appropriate files to project.

PC board—select this type of project if we intend to use our design with OrCAD

Layout. Follow the guidance of the PCB Project Wizard to add the appropriate files .

Programmable logic—select this type of project if we intend to use our design with Or

CAD Express. Follow the guidance of the Programmable Logic Project Wizard to add

the appropriate files to our project.

Schematic—select this type of project if none of the other project types apply. Using this option, Capture creates a basic project containing only the design file.

34

To create a new design From the File menu, choose New, then choose Design.

The design opens in a new PCB project manager and a new schematic page

displays.

To create a new schematic page

On the File tab of the project manager, select the schematic folder that requires a

new schematic page.

Click the right mouse button and choose New Page from the pop-up menu. A

new schematic page appears within the schematic folder we selected in step 1.

To create a new library

From the File menu, choose New, then choose Library

The library opens in the project manager and a Library Cache folder is added to

the project manager, or the library opens in the existing open project manager

and a library cache is added.

Opening existing projects, designs, and libraries

we can open an existing project, design, library or VHDL file. Existing schematic

pages can only be opened from within designs and libraries

To open an existing project

From the File menu, choose Open, then choose Project. The Open Project dialog box displays.Select a project (.OPJ) or type the name in the File name text box, then choose the Open button. The project opens in the project manager.

To open an existing design

From the File menu, choose Open, then choose Design The Open Design dialog box displays.

34

Select a design (.DSN) or type the name in the File name text box, then choose the Open button. The design opens in the project manager.

34

34

To open an existing schematic page

In the project manager, select the File tab and double-click the icon of a schematic folder; this Expands the folder and reveals the schematic pages it contains.

Double-click on the icon of the schematic page we want to open. The schematic page opens in a schematic page editor window.

To open an existing library

1 From the File menu, choose Open, then choose Library. The Open Library dialog box displays.

2 Select a library (.OLB) or type the name in the File name text box, then choose the Open button.The library opens in the project manager.

Working with files in a project

34

Using the project manager, we can add or delete project files. we can add any file to our project, including libraries and VHDL files. Files not in ASCII format, or a Capture generated format, may not appear as expected when opened in Capture.

To add a file to project

1 In the project manager, select the folder to which we want to add a file.

2 From the Edit menu, choose Project. The Add File to Project Folder dialog box displays.

3 Select the file we want to add and choose the Open button. The file is added to the project.

Or

1 Drag the file from the Windows Explorer into the folder in the project manager.

To delete a file from a project

1 In the project manager, select the file we want to delete.

2 Press the D key. The file is removed from the project.

Saving projects, designs, and libraries

When the project manager window is active, we can save a new or existing project, design, or library. The Save command saves all open documents referenced by the project, as well as the project itself.

The Save As command saves files depending on what we have selected in the project manager.

- If one or more designs or libraries are selected, we are prompted to save each file in turn.-If no top-level folders (Design Resources or Outputs) are selected, and items other than

designs or libraries are selected, the Save As command is unavailable.-If no designs or libraries are selected in the project manager, you are prompted to save the project.

To save a new design or library

With the design or library selected in the project manager, from the File menu, choose Save. The Save As dialog box displays.

34

Enter a name for the design or library in the File name text box, specify a location, then choose the Save button.

The design or library is saved, and the project manager remains open. When we close the project, Capture prompts we to save the project file.

To save an existing project

With the Design Resources or Output folder selected, choose Save from the File menu.

The project is saved, and remains open in the Capture session frame.

CLOSING A PROJECT

To close a project

From the project manager’s File menu, choose Close Project. When we close a project, a dialog box displays, asking if we want to save changes.

To quit Capture

From the project manager’s File menu, choose Exit.

Choose Yes to save the specific document Choose Yes All to save all documents in the project. Choose No to close the document without saving it. Choose No All to close all open documents without saving them. Choose Cancel to abort closing the project.

SETTING UP PROJECT

Capture provides different levels of configuration. Using commands on the Options menu, we can:

Customize the working environment specific to our system (using Preferences). Create default settings for new designs (using Design Template). These settings stay

with the design as design properties even if it is moved to another system with different preferences.

Override settings in individual designs (using Design Properties) or individual schematic pages (using Schematic Page Properties).

Regardless of which Capture window is active, the Options menu has a Preferences command and a Design Template command. In addition, the Options menu contains commands specific to the current active window. For example, the project manager’s Options menu contains the Design Properties command, while the

34

schematic page editor’s Options menu contains the schematics page properties command.The settings in the Preferences dialog box determine how Capture works on our system, and persist from one Capture session to the next because they are stored in the Capture initialization (.INI) file on our system. If we pass projects to others, they won’t inherit our Preferences settings. This means we can set colors, grid display options, pan and zoom options, and so on to our liking and be assured that our settings will remain, even if we work on a project created on another system.

The Design Template dialog box determines the default characteristics of all the projects created on our system. Because a new project inherits characteristics from the current Design Template settings, it’s a good idea to check the settings before we create a new project.

Once we begin working on a project, we can customize its particular characteristics by choosing Design Properties from the Options menu when we are in the project manager or Schematic Page Properties when we are in the schematic page editor.

DEFINING SELECTION OPTIONS

we can specify whether objects are selected when the selection border intersects them

or if the objects are selected only when they are completely enclosed in the selection

area. we can also change the maximum number of objects displayed at high resolution

while dragging, and set tool palette visibility in both the schematic page editor, and the

part and symbol editor.

34

Select tab of the Preferences dialog box

To define selection options

From the Options menu, choose Preferences, then choose the Select tab.

For the schematic page editor and the part editor, set these options:

Area Select. Specify whether to select objects that are inside and

intersecting the selection border or only objects that are fully enclosed by the

selection border.

Maximum number of objects to display at high resolution while

dragging. If we drag more objects then we specify here, we will see

rectangular placeholders for the objects as we drag them.

Show Palette. Select this check box to make the tool palette visible;

deselect it to make the tool palette invisible.Click OK.

34

Setting miscellaneous options

we can specify the default fill, line style and width, and color for graphics objects,

define the font used in the project manager and session log, render TrueType fonts

with strokes (for printing and plotting), and set whether to enable auto recovery for our

project and how often. In addition, we can enable intertool communication, which is

the method that Capture uses to communicate with other OrCAD software, such as

OrCAD Express, OrCAD PSpice, and OrCAD Layout.

Miscellaneous tab of the Preferences dialog box

To set miscellaneous options

1 From the Options menu, choose Preferences, then choose the Miscellaneous tab.

2 For the schematic page editor and the part editor, set these options:

Fill Style. Select the fill pattern to be used when drawing rectangles, ellipses, and

close shapes drawn with the polyline tool.

Line Style and Width. Select the line style and width used for lines, polylines,

rectangles, ellipses.

34

For the schematic page editor, set this option:

Color. Select the color used for graphic object (rectangles, ellipses, and closed

polylines).

Set the following options:

Project Manager and Session Log.

Select a font for display text in the project manager and session log. If we select this option, a standard Windows dialog box for font selection appears. Select a font, style, and size from the dialog box, then click OK.

Text Rendering.

The text rendering options affect how text on a schematic page appears on your

screen, and how it is printed or plotted. The Render TrueType fonts with strokes

option displays text as a series of lines, connected to resemble the outlines of the

corresponding TrueType letters or numbers they represent. Enabling the Fill text

option causes the text outlines to be filled in.

Auto Recovery.

Select whether to enable auto recovery for our project and, if so, the interval

between saves. we can specify any interval between five minutes and 120 minutes.

When the time interval is up, any design, library, or VHDL file in your project that

hasn’t been saved, or has been modified since the last save, is saved as a temporary

file (with an .ASP extension) in the WINDOWS/ TEMP/ AUTOSAVE directory.

When we close our project normally, the / AUTOSAVE directory and temporary

files are deleted. In cases of power outages or system crashes, however, the

temporary files are saved. When we restart Capture, it loads the auto recovered files,

showing “Restored” in their title bars. we must use the Save As command and

provide a filename to have an auto recovered file overwrite the original file.

Auto Reference.

Select whether to enable automatic annotating of reference designators when parts

are placed.

34

Intertool Communication. Select whether to enable intertool communication

(also known as ITC), so that you can test and display design information using other

OrCAD software (such as Layout, PSpice, and Express) in conjunction with Capture.

Capture processes its tools faster when intertool communication is not selected.

Click OK.

Setting text editor options

Capture’s text editor options include automatic highlighting of VHDL keywords,

comments, or quoted strings. We can also set the font, the tab spacing, and enable or

disable the highlighting feature.

Text Editor tab of the Preferences dialog box

34

To set text editor options

From the Options menu, choose Preferences, then choose the Text Editor tab.

Set these options:

Syntax Highlighting. Select the color to use to highlight VHDL keywords,

comments, and quote.

Current Font Setting. Click Set to change the font setting for the text editor to values

other than those displayed.

Tab Spacing. Set the tab spacing for the text editor.

Check the Highlight Keywords, Comments, and Quoted Strings option to have

those VHDL items highlighted in the text editor. The colors used to highlight

these items are the ones set in the Syntax Highlighting group box.

If we want to reset the text editor options to the Capture default values, click the Reset

button.

Click OK.

SETTING UP PROJECT TEMPLATES

The options that we define in the Design Template dialog box are the default settings

for all new projects, and for schematic pages you add to an existing project. we can

override some of these options for individual projects or schematic pages. Some of the

things we can define in the Design Template dialog box are:

Fonts. we can define the fonts for schematic page objects that contain text,

such as part references and values.

Title Block. we can specify the text to appear in title block fields, as well as

the path and filename of the library containing the title block. This affects

new projects, as well as new schematic pages in existing projects.

Page Size. we can specify whether inches or millimeters are used as the

unit of measure, the width and height of a schematic page, and the spacing

between pins.

Grid Reference. For horizontal and vertical border grid references, we can set

34

the number of border grid references to display in either direction, whether the

grid references are alphabetic or numeric, whether they increment or

decrement across the schematic page, and how wide grid reference cells are.

we can also make the border, grid references, and title block visible or invisible.

This affects new projects, as well as new schematic pages in existing projects.

Hierarchy. For hierarchical blocks and part instances that have their

Primitive property set to Default, we can specify if we want Capture to treat

each as primitive (cannot descend into attached schematic folders) or

nonprimitive (can descend into attached schematic folders).

SDT Compatibility. we can specify which Capture properties map to which

OrCAD Schematic Design Tools (SDT) part fields when saving a project in

SDT format.

Defining title block information

There are two types of title blocks: default and optional.

we specify the information that goes into the default title block in the Title Block tab

of the Design Template dialog box. Capture places a default title block in the lower right

corner of each schematic page (if a library and title block name are specified), and

places the information we enter in the text fields in the Title Block tab into the title

block. This information is also used in reports created by the commands on the Tools

menu. This affects new projects, as well as new schematic pages in existing projects.

we can set the default title block to be visible or invisible on an existing schematic

page by changing the setting in the Grid References tab in the Schematic Page Properties

dialog box.

we can place any number of optional title blocks anywhere on the schematic page

using the Title Block command on the Place menu. Optional title blocks display

information that you define as property values for the title block symbol.

34

Title Block tab of the Design Template dialog box

Capture provides default title block symbols in the CAPSYM.OLB library. One such

title block is shown below. The text shown in curly braces acts as property text

placeholders. we can specify the value by double-clicking on the text and supplying

a value. we can control the visibility by selecting or deselecting the Visible check box

in the Display Properties dialog box.

Title block

34

To choose a title block and define the text it contains

1 From the Options menu, choose Design Template, then choose the Title Block tab.

2 In the Text group box, enter the information we want to appear in the title block.

3 In the Symbol group box, enter the path and filename of the library containing the title block.

The Library Name text box can be left blank if you are using title block

from the CAPSYM.OLB library and CAPSYM.OLB has not been moved to

a different directory from where it was installed.

If weare using a custom title block, then put thefull path and file name for

the library in the Library Name text box.

4 Enter the exact name of the title block into the Title Block Name text box. Symbol

names are case sensitive and space sensitive.

5 Click OK.

Setting the schematic page size for new projects

For new projects, we can specify the default unit of measure, the default width and

height of schematic pages, and the spacing between pins. The value we enter in the Pin-

to-Pin Spacing text box defines how close together pins are placed in the part editor.

It also defines the grid spacing (the space between grid dots or grid lines)

Page Size tab of the Design Template dialog box

34

To set up the schematic page size

1 From the Options menu, choose Design Template, then choose the Page Size tab.

2 In the Units area, select the default unit of measure for new projects. This setting

only affects the schematic page editor, not the part editor.

3 Select the default schematic page size for new projects. For each schematic page

size (A, B, C, D, E, and Custom if the unit of measure is Inches; or A4, A3, A2, A1,

A0, and Custom if the unit of measure is Millimeters) you can specify the width and

height. The values that you enter in the Width and Height text boxes become the

dimensions for each page size. You cannot change these dimensions for individual

schematic pages, although you can select a different page size, or choose to define a

custom size.

4 In the Pin-to-Pin Spacing text box, specify the default spacing between pins. The

value you enter in this text box defines how close together pins are when you place a

part on a schematic page. It also defines the grid spacing (the space between grid

dots or grid lines). You cannot change this value for existing projects or individual

schematic pages.

Defining the grid reference

we set the border’s grid references to display either horizontally or vertically,

alphabetically or numerically, incrementally or decrementally across the schematic page,

and the width of their cells. You can also make the border, grid references, and title block

visible or invisible on the screen and on schematic pages you print. The settings affect

new projects and new schematic pages in existing projects.

34

Grid Reference tab of the Design Template dialog

To define the grid reference

1 From the Options menu, choose Design Template, then choose the Grid Reference tab.

2Specify the number of border grid references, whether they are alphabetic or numeric,

whether the grid references increment (Ascending) or decrement (Descending) across

the schematic page, and how wide the grid reference cells are.

3For the border, title block, and grid reference, selects Displayed to have the item display on

screen or Printed to have the item appear on schematic pages you print..

34

LAYOUT

What is Layout?

Layout is one part for the PCB Design in which we place as well as route the components and set unit of measurements, grids, and spacing in orcad. With other softwares you also have to place and route the components in a similar way. For the placement and routing of the components we normally use Auto-placement and Auto-routing.

Repetition of the steps for board design :-

At first, we have created a netlist from our schematic diagram by using capture.

Layout includes design rules in order to guide logical placement and routing.

That means, load the netlist into layout to create the board. At the same time you have to specify the board parameters.

Specify board parameters:- Specify global setting for the board, including units of measurements, gride and spacing. In addition , you create board outline and define the layerstacks, padstacks, and vias.

Place components:- Use the component tool in order to place manually the components which are fixed by the system designer on yhr board or otherwise Auto- placement.

Route the board:- Use different routing technologies to route the board and take advantage of push and shove, in which moves the tracks to make room for thr track you are currently routing as well as you can also auto route the board.

Provide finishing of the board:- layout supplies an ordered progression of commands on the Auto menu for finishing your design. These commands includes Design Rule Check, clean up design, Rename components, back Annotate, Run post processor, and create reports.

43

The Design Window:

The design window provides a graphical display of printed circuit board, it is a primary window you use when design your board. It also provides tools to facilitate the design process such as to update components and design rules violations. The design window appears when you open a new existing board.

The Library Manager

The Library Manager Window is used to view, edit and create footprints and footprints libraries. we can assign footprints to components in board. we can also modify and change footprints pad stacks in the library manager. The library manager is split into two windows one is library manager and second is footprint window.

44

To open the library manager

Choose the library manager toolbar button or from the file menu, choose the library manager.

The session log

The session log lists all the events that have occurred related to the currently open board. If we are facing any problems during designing layout then we can see all the errors in the session log and verify our design errors.

To open the session log:

From the file menu, choose text editor appears like a notepad.

From the text editor’s file menu, choose open. The open dialog box appears.

The toolbar

By choosing a tool in the toolbar, we can quickly perform the most frequent layout tasks. When we move the pointer over a toolbar button, the button’s name appears below the button.

45

46

47

48

Method to create a board with Layout Plus:

Ensure that net list with all footprints and necessary information has been created.

Create a directory in which the schematic design, net list, and boar will co-exit and put the

schematic design and net list. OrCad provides a directory for this purpose.

From the layout session frame’s file menu, choose New. The load template file in the dialog box

displayed.

Design window

49

Select the technology template (.TCH), then choose the open button and load the net list in other

box.

Then apply the auto ECO.

If necessary, respond to link footprints to component dialog.

Draw the board outline by using the obstacle tool in the tool bar.

Setting board parameters:

There is some parameter which should be set before placing the components on board. They are

as follows:-

Set Datum

Create a board outline

Set units of measurements

Set system grid

Add mount holes

Creating of board outline:

Board outline is the graphical representation of the size of the actual PCB board. So it is the main

step in layout, to draw the board outline of the actual size of PCB board.

50

Placement of components:

Placement of components means that to place the components in designed box. A designer should

follow the following steps before going for it:-

Optimize the board for component placement.

Load the placement strategy file.

Place components on the board.

Optimize placement using various placements

Components can be placed by using two techniques:-

1) Manual placement of components

2) Auto placement of components

Choose the components tool bar button. From the pop up men, choose the queue for placement.

The components selection criteria dialog box appears. Enter the reference designator of the

components that we want to place in the appropriate text box, and click ok. Drag the components

to desired location, place it there.

51

Conductor Routing in Layout:-

After placing all the components the other main step is to route the board from the electrical

connections between the components. One may route board manually or automatically by auto

router.

100% auto routing can be achieved only when components are placed in the order of functional

flow of electronic circuit. The main routing tool available in OrCad is as flow:-

Add/edit route mode

Edit segment mode

Shove track mode

Auto path route mode

Design Rule Check:-

In manual designs every thing was checked as a possible source of error. Components sizes, hole

sizes, conductor widths and clearance, land-to-hole-ratio, board areas to be free of components,

clearance to the edges, positional accuracy and of course electrical interconnections had tad to be

personally reviewed with a great deal of care. After completing the design of printed circuit board

with the help of an EDA-Tool, a designer has again to verify the PCB in order to find out errors.

Such type of verifications/design rule check contains beside the general verifications commonly

two types:-

Physical verification

Electrical verification

52

Post processing:-

Post processing can be done once the design is completed in all aspects. The common way is still

a process to generate GERBER data and NCD files which can be used for photo plotting and for

steps of CNC manufacturing and PCB- drilling.

POWER SYSTEM DESIGN

First part of electronics ckts. is power. The main power supply is in AC but mostly electronic

ckts. work with DC. So a system is required to convert ac to dc and these sources should able to

produce stable supplies. Power supplies may be used in. may be of different types such as

regulated, unregulated, smps etc.

Unregulated power supplies

These are the power supplies in which the out put is not constant. That it is varies with input

voltage, load, and also effected by the environment conditions such as temperature, etc. so

these are the variable supplies. Commonly these supplies are not employed as there efficiency

is very less. The unregulated power can be obtained using rectifying circuit after AC supply.

Regulated power supplies

These are the power supplies in which the output voltage is constant, i.e. the out put voltage

is independent of the input voltage, load and other external conditions. So to obtain the

regulated voltage using different regulators. The regulator voltage is mainly the DC voltage, it

may AC to or DC to DC voltage. A better approach to power supply design is to use enough

capacitance to reduce ripple to low level, then use an active feedback circuit to eliminate the

remaining ripple and dependence of output voltage on input, load and environment conditions.

These active devices are known as Regulators. These regulators can be used to produce

negative and positive voltage of required value.

53

The voltage regulators are of three types:-

1) Constant positive voltage regulators

2) Constant negative voltage regulators

3) Variable voltage regulators

Constant positive voltage regulators:-

These are the regulators which are able to produce positive and constant voltage. Some of them

are given below:-

S. no. Name of regulator Output voltage

1 LM 7805 5v

2 LM 7810 10v

3 LM 7812 12v

4 LM 7815 15v

These regulators are used according to the required voltage need.

Constant negative voltage regulators:-

These are also the constant output voltage regulator but there output is negative in polarity. These

regulators are also employed according to voltage requirements. Some of them are given below

with there outputs:-

S. no Name of regulator Output voltage

1 LM7905 -5v

2 LM7910 -10v

3 LM7912 -12v

4 LM7915 -15v

54

Variable voltage regulators:-

These are the regulator whose output voltage can be varied according to the desired need. These

regulators again of two types i.e.:-

Positive

Negative

The output of these regulators can be varied by varying the resistance of the variable resistance

which is connected to the adjustable pin the regulators. So these are the most commonly used

regulators in the electronic industry as wide range of stable voltage can be obtained from single

chip by varying the resistance connected to the adjustable pin of the regulators. The most

commonly variable regulators are:-

LM317 (it is positive regulator)

LM 337(it is negative regulator)

55

BIBLIOGRAPHY

www.google.com

www.eeast.biz

www.electrosoft.biz

www.techera.co.in

Study material by eeast

56