Design of Pcb Layout

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DESIGN OF PCB LAYOUT FORINVETRING AMPLIFIER USING CAD

Work done by

CHAREN K (13110106025)

DILLI PRASANTH (13110106035)

DEPARTMENT OF ELECRONICS AND

COMMUNICATION ENGINEERING

R.M.K COLLEGE OF ENGINEERING AND

TECHNOLOGY

PUDHUVOYAL

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NOVEMBER 2013

R.M.K

COLLEGE OF ENGINEERING AND TECHNOLOGY

ISO 9001:2008 CERTIFIED INSTITUTION

R.S.M NAGAR, PUDHUVOYAL-601206

GUMMIDIPOONDI TALUK, THIRUVALLUR DISTRICT.

BONAFIDE CERTIFICATE

DEPARTMENT - ELECTRONICS AND COMMUNICATION ENGINEERING

LABORATORY - ELECTRONICS SYSTEM DESIGN LABORATORY

SEMESTER - VII

Certified that this is a bonafide record work done

by

with register number. He is

a student ofELECTRONICS

AND COMMUNICATION ENGINEERING in the R.M.K COLLEGE OF

ENGINEERING AND TECHNOLOGY,

Pudhuvoyal.

Faculty in charge

Head of the department

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Principal

External examiner Date: Internal

examiner

Abstract:

CAD ( Computer Aided design ) is very essential fordesigning electronic circuits at various standards and complexity levels .

OrCAD software is primary software used for different purposes like

Designing, Simulation, and Debugging of electronic circuits . OrCAD PCBEditor is used for designing PCB layout of an electronic circuit . Lets

design and study the performance of a bjt inverting amplifier , which

gives amplified output signal with respect to the input signal with OrCAD

Pspice and schematic and its PCB layout with OrCAD PCB editor software.

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CONTENTS

Page no.

CHAPTER 1

INTRODUCTION

1.1 PCB designing

1.2 Types of PCB

1.3 PCB designing using CAD

CHAPTER 2

INVERTING AMPLIFER SCHEMATIC USING CAD

2.1 Orcad design environment

2.2 Starting capture2.3 Design of Inverting Amplifier2.4 Inverting Amplifier schematic

CHAPTER 3

PCB LAYOUT DESIGN

3.1 Layout3.2 Design window

Power system design

Bibliography

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CHAPTER 1

INTRODUCTION

1.1 PCB DESIGNING

PCB stands for PRINTED CIRCUIT BOARD. Printed circuit board (PCB)provides both the physical structure for mounting and holding thecomponents as well as the electrical interconnection between thecomponents. That means a PCB = PWB (printed wiring board) is theplatform upon which electronic components such as integratedcircuit chips and other components are mounted. A PCB consists of anon-conducting substrate (typically fiber glass with epoxy as resin)upon which the conductive patter nor circuitry is formed. Copper isthe most prevalent conductor although nickel, silver and tin are alsoused in some cases.

1.2 TYPES OF PCB

PCB may be of differentSingle sided PCBs

As the name suggest in these designs the conductive pattern isonly at in one side. And also the size is large in these case but these arecheap.Double sided PCBs

These are the PCBs on which the conduct ive pattern is inon both sides. The size of board is small in this case but it is costlier thanthat of above.

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

of conducting pattern and insulating material. Theconductive material is connected across the layers through platedthrough holes. The size of this PCB is smaller than that of double sided PCBbut it is very costly .PCBs may also be either rigid, flexible, or thecombination of two (rigid- flex). When the electronic components havebeen mounted on the PCB, the combination of PCB and components

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is an electronic assembly, also called PRINTED CIRCUIT ASSEMBLY.ThisAssembly is the basic building block for most of the electronicdevies.

1.3 PCB DESIGN USING CAD

CAD system for PCB designing requires following:

i. A computer system.ii. PCB design software like OrCad, CADSTAR, Protel, TANGO,

Mentor etc.

A photo plotter for art work generation.There are many enhanced features inelectronics design automation tools which not possible in the hand taping.

The main advantages are given below:i. Auto placementii. Auto routingiii. After routing, optimization of tracks can be done.iv. Provides physical design reuse modulesv. Electrical rule check (ERC)

vi. All the layers are generated from same design bygiving different options

vii. Bill of material can be generated which containsnumber of different components used.

viii. We can draw conductors as an arc, semi-circular atdifferent angles.

Design Rule Checkix. Advanced CAD systems have high speed analysis.x. CAD system provides all NCD files and Gerber data

files for photo plotting.

1.3.1BASIC DESIGN STEPS IN CAD- SYSTEM

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

1. Entry the schematic diagram.2. Net list file creation.3. Placement of components manually or automatically.4. Routing of the board using manual routing tools or

auto router

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CHAPTER 2

INVERTING AMPLIFER SCHEMATIC USING CAD

2.1 ORCAD DESIGN ENVIRONMENT

OrCad has a long history of providing individuals and teams with acomplete set of technologies that offer unprecedented productivity, seamless tool integration

, andexceptional value. New 10.5 release continues that tradition .Today'slower cost andyethighly sophisticated electronic design automation systems have created auniquechallenge to nearly every engineering department. Therefore the useof EDA tools has become increasingly important as product lifecycles havebecome shorter and shorter. Modern electronic design automation (EDA)tools are beginning to support a more efficient and integrated approach toelectronic. OrCad Capture design entry is the most widely used schematicentry system in electronic design today for one simple reason :fast anduniversal design entry. Whether you're designing a new analog circuit,revising schematic diagram for an existing PCB, or designing a digital block

diagram with anHDL module, OrCad Capture provides simple schematiccommands you need to enter, modify and verify the design for PCB. OrCadLayout offers PCB designers and PCB design teams the power andflexibility to create and share PCB data and constraints across the designflow. OrCad Layout delivers all the capabilities to designers need from netlistto place and route, to final output. The ease-of use and intuitive capabilitiesof OrCad Layout

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2.2 STARTING CAPTURE

The OrCAD Release 16.5 installation process puts Capture in the

\PROGRAMFILES\ORCAD\CAPTURE folder, and adds OrCAD 16.5 to the Programs

menu(available from the Start button).

From the Start menu, choose Programs. The Programs menu displays .From theCADENCE Release menu item, choose ORCAD CAPTURE CIS

2.2.1 The Capture session frame

Once we start Capture, we see the Capture session frame we do all yourschematic design and processing within this window .The minimized Session Log iconin the lower left portion of the Capture session frame is the session log. Thesession log provides information about everything we have done in thecurrent Capture session. Detailed information about this windowand the

other windows in Capture.

i. To start the capture work space . Click on file new project .

ii. Select the schematic button and enter the file name andclick OK .

Fig 2.1 : opening new project

Finally ORCAD Capture CIS workspace is created and it consist allnecessary elements required to design a electronic circuits . The workspacehas a dotted grid , where the components are placed from the list of librariesavailable using place parts option . Place parts can be found under , Place Place part option

2.2.2 THE PROJECT MANAGER

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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 suchas bills of materials and netlists .A project doesnt actually contain all the

resources. It merely points to the various files that the project uses .Forthis reason, we dont move or delete any files referenced by a project. Ifwe do, the project wont be able to find them. The project file is saved withan .OPJ file extension .It is an ASCII file, and can be viewed in any text editor.

Project manager folders

Design Resources folder is the design folder with the designsschematic folders and schematic pages, and a Design Cache folderthat shows all the parts usedon theschematic pages. Any schematic folders or schematic pages that we cr

eate areautomatically added to the design folder (in Fig. the design folder isnamedDESIGN3.DSN).

we can also add other files or information using the Project command onthe Edit menu The Library folder (in the Design Resources folder) shows theschematic part library files weve added to the project using theProject command on the Edit menu .

The Outputs folder shows the output of Captures processing tools.Generally, thesefilesinclude bill of materials reports and technologyspecific netlists Capture adds theappropriate 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 itmust have a single root module

The root module is defined as the top level of the design. That is, allother modules in the design are referenced within the root module .Withinthe project manager, we can expand or collapse the structure we see bydouble-clicking on a folder, or by clicking on the plus sign or minus sign tothe left of a folder .A plus sign indicates that the folder has contents thatare not currently visible; a minussign indicates that the folder is open and itscontents are visible, listed below the folder .It appears as a schematic folderwith a slash on it in a design file, or as a page in a VHDL file .Each project weopen has its own project manager window. we can move or copy folders or

files between projects by dragging them from one project manager windowto another (as well as to and from Windows Explorer). To copy rather thanmove items, press and hold the C key while we drag them. If we closea project manager window, we close the project .In the project managersFile tab, double-clicking on a schematic folder expands it and displays iconsfor each schematic page within the schematic folder. Then, if we double-clickon a schematic page icon, the schematic page opens in a schematic pageeditor. Or ,if the page is already open, its window becomes active .

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A design can consist of a single schematic page within a singleschematic folder, or a number of schematic pages within a number ofschematic folders. A schematic folder contains schematic pages in arelationship similar to the relationship between a directory and the files itcontains. Files are contained in a directory; schematic pages are contained ina schematic folder .A schematic page provides a graphical description of theelectrical connectivity of a design. It is made up of parts, wires, and otherelectrical symbols. A schematic page may also contain borders, title blocks,text, and graphics.

Capture acts on any schematic folders or schematic pages we haveselected within an active project manager window .For example, the Find andBrowse commands on the project managers Edit menu, the Print command on theproject managers File menu, and the various tools on the Tools menu, only apply tothe selected schematic folder or pag

2.3 DESIGN OF INVERTING AMPLIFIER

The BJT Inverting amplifier is designed in design window using theparameters available in the place parts tab

The components are placed in the design window from place part dialog

box .The components placed in the grid is connected using wire (w)The BJT inverting amplifier is designed with two voltage soruces

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2.3 INVERTING AMPLIFIER SCHEMATIC

To generate schematic graph and diagram for studying the

performance characteristics of the inverting amplifier , follow the steps givenbelow

Copy the circuit designed in the design window , which iswith respect to schematic domain .

Open new project under ( Analog and mixed A/D ) domainin order to simulate the electronic circuit under differentconditions .

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Thus a new work space is created similar to schematic domain .

Copy the inverting amplifier circuit and past it in the work space showabove . This will initiate the simulation process .

2.3.1 CREATE NEW SIMULATION PROFILE

To generate different simulations with respect to the designed circuit .It is necessary to create a simulation profile , under which all the simulationsare executed and stored .

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Click on PSPICE option new simulation profileThus new simulation profile window is displayed . Enter the name for newsimulation profile and click OK .

This action displays the simulation settings window , where the differentsimulations setting are available with respect to inverting amplifier , which is

designed in schematic root .

2.3.2 TYPES OF ANALYSIS ( SCHEMATIC ) .

The newly created simulation will open the gate way to different types

of analysis with respect to circuit designed using OrCAD .The different types of analysis with respect to simulation of circuit are

1. Time Domain ( Transient )2. DC sweep3. AC sweep / Noise

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4. Bias point2.3.3 SIMULATION PINS

This below figure displays the voltage and current pins represented as(V) and (I) respectively are used to generate the simulation output with

voltage or current input respectively .

These pins are placed on some specific location in the circuit designed toget the simulation of circuit at that specific point

SIMULATION OF INVERTING AMPLIFIER

1. Time Domain ( Transient ) Analysis .

Transient analysis provides for plotting of any time-domainwaveform. Available variables include digital state, voltage, current, power,energy, charge, resistance, capacitance, inductance, B field, and H field. Avariety of variables and mathematical functions are available to simplifyplots.

To perform Time Domain analysis :

i. Select Time Domain ( Transient ) option in thesimulation settings dialog box.

ii. Under the time domain ( transient ) , there are manyfactors based on which the simulation is carried out .

iii. Select the General settings check box .iv. Under general settings option , enter run to time = 10m ,

start saving data after = 0 , and maximum step size = 10usec

v. Click apply okvi. Press f11 to run the simulation.

Under time domain , we can analysis the performance of the circuit at

various temperature by choosing the Temperature Sweep check

box along with the General settings check box.

Under Temperature Sweep option , enter different temperature at which

the simulation/performance of the device is

1. Enter different temperature range as [ 15 20 30 ] .2. Click apply and then OK.3. Run the simulation

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The Time domain ( transient ) Simulation output is given below

The simulation out put with respect to Temperature sweep output fordifferent temperature [ 15 20 25] is given below .

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2. DC SWEEP ANALYSIS

Computation of voltages and currents as a function of (a) a variable dc

voltage, or (b) a variable dc current, or (c) a variable parts value (example:

resistor), or (d) a variable parameter (example: current gain of a transistor .

1) Select the DC sweep in scroll and enter the valuewith respect to the circuit designed .

2) Enter the source name , start , end andintermediate value to get the simulated graph for DC sweep analysis .

The simulated output with respect to DC sweep is given as :

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3. AC SWEEP / NOISE

Computation of voltages and currents within a circuit as a function of avoltage or current with constant amplitude but with variable frequencywithin a specified range - based on certain starting conditions (bias point).

This analysis corresponds to the classical small signal ac analysis veryoften used by handheld calculations (example: Xc=1/C).

1) Enter the AC input as 100ms in Vsin

And enter the parameters in simulation setting dialog box as show below.

The output schematic with respect to AC sweep is given as :

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4. BIAS POINT ANALYSIS

Bias analysis is a .DC analysis where the quiescent point is studied. Youcan make a bias analysis to determine the bias point of your circuit and seeits variation with temperature, a design parameter, supply voltage.

The Bias Point schematic output with respect to circuit is given as :

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Design of Pcb Layout

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