Analogue Design and Simulation using OrCAD Capture and PSpice

320 Pages·2011·27.314 MB·English

by  Dennis Fitzpatrick (Auth.)

Analog Design and
Simulation using OrCAD
Capture and PSpice
Dennis Fitzpatrick
AMSTERDAM(cid:1)BOSTON(cid:1)HEIDELBERG(cid:1)LONDON(cid:1)NEWYORK(cid:1)OXFORD
PARIS(cid:1)SANDIEGO(cid:1)SANFRANCISCO(cid:1)SINGAPORE(cid:1)SYDNEY(cid:1)TOKYO
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Preface
ix
The Cadence/OrCAD family of Electronic Design Automation (EDA) software
provides a complete design flow from schematic entry to circuit simulation
through to PCB layout. The circuit is drawn using the Capture or Capture CIS
schematic editor and circuit simulations are performed using PSpice. The
schematic diagram is translated into a printed circuit board design using
CadenceAllegroorPCBEditorwhichhasreplacedOrCADLayout.Thebookhas
beenwrittenusingthelatest16.5softwarereleaseandcanbeusedwithprevious
softwarereleases and theevaluation demoCD.
This book will benefit anybody with an interest in using the Cadence/OrCAD
professional simulation software for the design and analysis of electronic
circuits.Thebookprovidesapracticalhandsonapproachtousingthesoftware
andattheendofeachchapterthereareexerciseswithstepbystepinstructionsto
complete.
Thanks are due to the technical staff at the University of West London, Keith
Pamment and Seth Thomas for reviewing the simulation exercises, Taranjit
KukalandAlokTripathifromCadenceforreviewingthetechnicalaspectsofthe
book and Parallel-SystemsUK for their support.
Instructions
xi
Throughout the book, bold type will indicate tool specific keywords and also
whichmenustoselect,forexample,themenuselectiontocreateanewprojectis
shownbelow.
The instruction sequence will be, File > New > Project. The words in bold
indicatewhichsuccessivemenustoselectfromthetoptoolbar,asshownabove.
Arightmousebuttonclickwillbewrittenasrmb.Forexample,selectthepartin
the schematic and rmb > rotate.
Boldtypeisalsousedtonameanydialogboxandwindowsthatmayappear.For
example, the Create PSpice Projectwindowis shownbelow.
LIMITS OF ORCAD DEMO CD
The OrCAD demo CD, which is free to download or order from
www.Cadence.com, is not time limited, it is only limited in functionality and
sizeoftheschematic.YoucanusethedemoCDformostoftheexercisesinthis
book. However,thenumberof limits from16.5 onwardshaschanged.
PRE-16.5
For PSpice simulation, you are limited to 64 nodes, 20 transistors, two sub-
circuits or 65 digital primitives and 10 transmission lines (ideal or non-ideal)
withnotmorethanfourpairwisecoupledlines.ThemaximumnumberofTlines
is limitedto four.
xii Instructions
Theinternalsubcircuitnodesforopampscounttowardsthetotalnodecount.So
use the uA741 from the eval library on the demo CD, which has 19 internal
nodes. Fordigital circuits,the maximum numberof nodes is limitedto 250.
In Capture you can create and view designs but cannot save designs that have
morethan64netsor60parts.TheCaptureCISdemodatabaseislimitedto10
parts.Youcannotcreatepartswithmorethan14pinsandyoucannotsavepart
libraries withmorethan 15 parts.
TheModelEditorislimitedtodiodemodelsandtheModelImportWizardonly
supports twopin parts and models.
The Stimulus Editor is limitedto sine waves and digitalclocks.
Onlysimulation data created in the demoversion can be displayed.
The Magnetic Parts Editor can only be used to design power transformers. The
Magnetic Parts Editor supplied database cannot be edited and only contains
asingle magnetic core.
POST-16.5
From16.5onwards,forPSpicesimulation,thenumberofnodeshasincreased
to 75 nodes and there is no subcircuit limit.
There is no limit to stimulus generation using the StimulusEditor.
In Capture you can create and view designs but cannot save designs that have
more than 75 nets or 60 parts.
You cannot havemore than 1000 parts inthe CIS database.
You cannot createparts withmore than 100 pins.
CHAPTER 1
Getting Started
1
Chapter Outline
1.1 StartingCapture 1 1.5 Summary 12
1.2 Creating aPSpiceProject 2 1.6 Exercises 13
1.3 Symbolsand Parts 7 Exercise 1 13
1.3.1 Symbols 7 Exercise 2 15
1.3.2 Parts 8 1.7 ExtraLibrary Work 17
1.4 Design Templates 10
Thoseofyouwhoarefamiliarwithsettingupprojectsanddrawingschematics
inCapturemaywanttoskipthischapter,asithasbeenwrittenforthoseofyou
whohavelittleornoexperienceofusingCapture.Thischapterwilldescribehow
to start Capture and how to set up the project type and libraries for PSpice
simulation.
Attheendofeachchaptertherearesomeexercisestodoandasyougothrough
the book, each chapterwill buildupon the exercises fromprevious chapters.
1.1 STARTING CAPTURE
Circuit diagrams for PSpice simulation are drawn in either Capture or Capture
CISschematiceditor.TheCISoption,whichstandsforComponentInformation
System,allowsyoutoselectandplacecomponentsfromacomponentdatabase
instead of selecting and placing components from a library. For this book, it
doesnot matterwhether the circuits are drawnin Captureor Capture CIS.
If you have the OrCAD software installed, launch Capture or Capture CIS, by
clickingon:
Start > Program Files > OrCAD xx.x > Capture
or
Start > Program Files > OrCAD xx.x > Capture CIS
AnalogDesignandSimulationusingOrCADCaptureandPSpice.DOI:10.1016/B978-0-08-097095-0.00001-5
Copyright(cid:1)2012ElsevierLtd.Allrightsreserved.
2 Analog Design and Simulation using OrCAD Capture and PSpice
where xx.x is the version number, e.g. 10.5, 11.0, 15.5, 15.7, 16.0, 16.2, 16.3
or 16.5.
Atthe time of writing this book, the current version is 16.5 and is started by:
Start > Program Files > Cadence > Release 16.5
If you have the Cadence software installed, the tools are installed under the
Allegroplatformname.Inthiscase,onlyCaptureCISisavailableandisbranded
as DesignEntry CIS:
Start > Program Files > Allegro SPB xx.x > Design Entry CIS
1.2 CREATING A PSPICE PROJECT
New designs started in Capture will automatically create a project file (.opj)
whichwillreferenceassociatedprojectfilessuchastheschematics,librariesand
output report files.
Beforethecircuitdiagramisdrawn,theprojecttypeandlibrariesrequiredforthe
projectneedtobesetup.Firstofallanewprojectiscreatedbyselectingfromthe
top toolbar:
File > New > Project
IntheNewProjectwindow(Figure1.1),youenterthenameoftheprojectand
thenyouhaveachoice ofone of four project types:
(cid:1) Analog or Mixed A/D is used for PSpice simulations.
(cid:1) PC Board Wizard is used for schematic toPCB projects.
FIGURE 1.1
Creatinganewproject.
Getting Started CHAPTER 1 3
(cid:1) Programmable LogicWizard is used for CPLD and FPGAdesigns.
(cid:1) Schematic is usedfor schematic and wiring diagrams.
WhenyouselectaProjecttype,theTipforNewUsersgivesabriefexplanation
of the project type. For PSpice projects, select Analog or Mixed A/D. This will
activatethe PSpicemenu on the top toolbar inCapture.
It is recommended that a new directory location (folder) is created for each
new project. This can be done by clicking on the Browse. button shown
inFigure1.1,whichopensuptheSelectDirectorywindowshowninFigure1.2.
FIGURE 1.2
Creatingaprojectfolderlocation.
ByselectingtheCreateDir.button,theCreateDirectorywindow(Figure1.3)
appears,whichallowsyouto name the directory(folder).
FIGURE 1.3
Creatingtheprojectfolder.
The created folder, PSpice Exercises in this example, will appear in the Select
Directorywindow.However,youmusthighlightandselectthefolderbyclicking
twice with the left mouse button, which will show the ’open’ yellow icon as
showninFigure1.4.Afurthersubdirectoryorfoldercanbecreatedbyclicking
on the Create Dir. inthe Select Directory windowbutton and following the
same procedureabove.
4 Analog Design and Simulation using OrCAD Capture and PSpice
The project folder location will then appear in the Location box of the New
Project window(see Figure 1.1).
FIGURE 1.4
Theprojectfolderhasbeen
selected.
An alternative method of creating the project folder is to type in the folder
locationdirectlyintotheLocationboxintheNewProjectwindowinFigure1.1
and Capture will automaticallycreatethe folder.
NOTE
Itisacommonmistaketocreateaprojectfolderandnotselectthefolder.Makesure
youdoubleclickonthecreatedfoldernameintheSelectDirectorywindow(Figure1.4).
ThenextwindowtoappearistheCreatePSpiceProjectwindow,whichsetsup
the project forPSpicesimulation (Figure 1.5).
Thepull-downmenuoptionallowsyoutoselectpreconfiguredCapture-PSpice
libraries for the project. The most commonly used option for new projects is
Simple.opj, which adds the following fivedefaultlibraries tothe project:
Analog.olb
Breakout.olb
Source.olb
Sourcstm.olb
Special.olb
Getting Started CHAPTER 1 5
FIGURE 1.5
CreatePSpiceProject.
These libraries contain the most commonly used parts for PSpice projects and
are recommended for new projects.
There is also an option to create updated versions of an existing project, i.e. to
createanewerversion2basedupontheoriginalversion1project.IntheCreate
PSpiceProjectWindow(Figure1.5),select thefunctionCreatebaseduponan
existingprojectandthenBrowsetoselectanexistingproject.Thiswillcopythe
existingprojectandallitsassociatedfilesintothenewproject.Thisissimilarto
using the File >SaveAs function.
IftheCreateablankprojectoptionisselected,thennoCapture-PSpicelibraries
are added to the project. The libraries can be added later. This will be demon-
strated in oneof the exercises at the endof this chapter.
Whenanewprojectiscreated,aProjectManagerwindowiscreated(Figure1.6)
whichshowstheabsolutepathtothelibraries.RememberthattheseareCapture
symbollibrarieswhichdefinethegraphicsfortheparts.TheyarenotthePSpice
modellibraries.TheCapturelibrariesareinstalledbydefaultandcanbefound,
depending on the OrCAD or Cadence software version you are using, for
example, at:
<software install path> OrCad > OrCAD_10.5 > tools > capture > library
> pspice
or
<software install path> Cadence > SPB_16.3 > tools > capture > library
> pspice