Orcad PSPICE User Manual

OrCAD PSpice®

User’s Guide

Copyright © 1998 OrCAD, Inc. All rights reserved.

Trademarks

OrCAD, OrCAD Layout, OrCAD Express, OrCAD Capture, OrCAD PSpice, and OrCAD PSpice A/D are registered trademarks of OrCAD, Inc. OrCAD Capture CIS, and OrCAD Express CIS are trademarks of OrCAD, Inc.

Microsoft, Visual Basic, Windows, Windows NT, and other names of Microsoft products referenced herein are trademarks or registered trademarks of Microsoft Corporation.

All other brand and product names mentioned herein are used for identification purposes only, and are trademarks or registered trademarks of their respective holders.

Part Number 60-30-636
First edition 30 November 1998
Technical Support	[phone]
Corporate offices	[phone]
OrCAD Japan K.K.	81-45-621-1911
OrCAD UK Ltd.	44-1256-381-400
Fax	[phone]
General email	[e-mail]
Technical Support email	[e-mail]
World Wide Web	http://www.orcad.com

OrCAD Design Network (ODN) http://www.orcad.com/odn

9300 SW Nimbus Ave.

Beaverton, OR 97008 USA

Contents

Before you begin xxiii

	Welcome to OrCAD . . . . . . . . . . . . . . . .	. . . . . . . . . . . . .	xxiii
	OrCAD PSpice overview . . . . . . . . . . . . .	. . . . . . . . . . . . .	xxiv
	How to use this guide . . . . . . . . . . . . . . .	. . . . . . . . . . . . . . xxv
	Typographical conventions . . . . . . . . .	. . . . . . . . . . . . . . xxv
	Related documentation . . . . . . . . . . . . . .	. . . . . . . . . . . . .	xxvi
	Online Help . . . . . . . . . . . . . . . . . .	. . . . . . . . . . . . .	xxvii
	If you have the demo CD-ROM . . . . . . .	. . . . . . . . . . . . . xxviii
	OrCAD demo CD-ROM . . . . . . . . .	. . . . . . . . . . . . . xxviii
	What’s New . . . . . . . . . . . . . . . . . . . .	. . . . . . . . . . . . . . xxix
Part one	Simulation primer
Chapter 1	Things you need to know 1
	Chapter overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .			1
	What is PSpice? . . . . . . . . . . . . . . . . . .	. . . . . . . . . . . . . . .		2
	Analyses you can run with PSpice . . . . . . . .	. . . . . . . . . . . . . . .		3
	Basic analyses . . . . . . . . . . . . . . . . .	. . . . . . . . . . . . . . .		3
	DC sweep & other DC calculations . . .	. . . . . . . . . . . . . . .		3
	AC sweep and noise . . . . . . . . . . .	. . . . . . . . . . . . . . .		4
	Transient and Fourier . . . . . . . . . . .	. . . . . . . . . . . . . . .		5
	Advanced multi-run analyses . . . . . . . .	. . . . . . . . . . . . . . .		6
	Parametric and temperature . . . . . . .	. . . . . . . . . . . . . . .		6
	Monte Carlo and sensitivity/worst-case	. . . . . . . . . . . . . . .		7
	Analyzing waveforms with PSpice . . . . . . .	. . . . . . . . . . . . . . .		8
	What is waveform analysis? . . . . . . . . .	. . . . . . . . . . . . . . .		8
	Using PSpice with other OrCAD programs . . .	. . . . . . . . . . . . . . .		9
	Using Capture to prepare for simulation .	. . . . . . . . . . . . . . .		9
	What is the Stimulus Editor? . . . . . . . .	. . . . . . . . . . . . . . .		9
	What is the Model Editor? . . . . . . . . . .	. . . . . . . . . . . . . . . 10

Contents

	Files needed for simulation . . . . . . . . . . . . . . . . . . . . . . . . . .	10
	Files that Capture generates . . . . . . . . . . . . . . . . . . . . . . .	10
	Netlist file . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	11
	Circuit file . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	11
	Other files that you can configure for simulation . . . . . . . . . . .	11
	Model library . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	12
	Stimulus file . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	13
	Include file . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	13
	Configuring model library, stimulus, and
	include files . . . . . . . . . . . . . . . . . . . . . . . . . .	13
	Files that PSpice generates . . . . . . . . . . . . . . . . . . . . . . . . . .	14
	Waveform data file . . . . . . . . . . . . . . . . . . . . . . . . . .	14
	PSpice output file . . . . . . . . . . . . . . . . . . . . . . . . . . .	14
Chapter 2	Simulation examples 15
	Chapter overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	15
	Example circuit creation . . . . . . . . . . . . . . . . . . . . . . . . . . . .	16
	Finding out more about setting up your design . . . . . . . . . . . .	21
	Running PSpice . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	22
	Performing a bias point analysis . . . . . . . . . . . . . . . . . . . . .	22
	Using the simulation output file . . . . . . . . . . . . . . . . . . . . .	24
	Finding out more about bias point calculations . . . . . . . . . . . .	25
	DC sweep analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	26
	Setting up and running a DC sweep analysis . . . . . . . . . . . . . .	26
	Displaying DC analysis results . . . . . . . . . . . . . . . . . . . . . .	28
	Finding out more about DC sweep analysis . . . . . . . . . . . . . .	31
	Transient analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	32
	Finding out more about transient analysis . . . . . . . . . . . . . . .	36
	AC sweep analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	37
	Setting up and running an AC sweep analysis . . . . . . . . . . . . .	37
	AC sweep analysis results . . . . . . . . . . . . . . . . . . . . . . . .	39
	Finding out more about AC sweep and noise analysis . . . . . . . .	41
	Parametric analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	42
	Setting up and running the parametric analysis . . . . . . . . . . . .	43
	Analyzing waveform families . . . . . . . . . . . . . . . . . . . . . .	45
	Finding out more about parametric analysis . . . . . . . . . . . . . .	48
	Performance analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	49
	Finding out more about performance analysis . . . . . . . . . . . . .	51

iv

						Contents
Part two	Design entry
Chapter 3	Preparing a design for simulation		55
	Chapter overview	. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55
	Checklist for simulation setup . . . . . . . . . . . . . . . . . . . . . . . . . 56
	Typical simulation setup steps . . . . . . . . . . . . . . . . . . . . . . . 56
	Advanced design entry and simulation setup steps . . . . . . . . . . . 57
	When netlisting fails or the simulation
	does not start . . . . . . . . . . . . . . . . . . . . . . . .					. . . . 58
	Things to check in your design			. . . . . . . . . . . . . . . . . . . . 58
	Things to check in your system configuration . . . . . . . . . . . . 59
	Using parts that you can simulate		. . . . . . . . . . . . . . . . . . . . . . . 60
	Vendor-supplied parts . . . . . . . . . . . . . . . . . . . . . . . . . . . 61
	Part naming conventions . . . . . . . . . . . . . . . . . . . . . . . . 61
	Finding the part that you want			. . . . . . . . . . . . . . . . . . . . 62
	Passive parts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64
	Breakout parts . . . . . . . . . . . . . . . . . . . . . . . . . . . .					. . . . 65
	Behavioral parts . . . . . . . . . . . . . . . . . . . . . . . . . . .					. . . . 66
	Using global parameters and expressions for values				. . . . . . . . . . . . 67
	Global parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67
	Declaring and using a global parameter . . . . . . . . . . . . . . . 67
	Expressions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69
	Specifying expressions . . . . . . . . . . . . . . . . . . . . . . . . . 69
	Defining power supplies . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74
	For the analog portion of your circuit . . . . . . . . . . . . . . . . . . . 74
	Defining stimuli . . . . . . . . . . . . . . . . . . . . . . . . . . . . .					. . . . 75
	Analog stimuli . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75
	Using VSTIM and ISTIM . . . . . . . . . . . . . . . . . . . . . . . . 76
	If you want to specify multiple stimulus types				. . . . . . . . . . . 77
	Things to watch for	. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79
	Unmodeled parts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79
	Do this if the part in question is from the OrCAD libraries					. . . . 79
	Check for this if the part in question is custom-built . . . .					. . . . 81
	Unconfigured model, stimulus, or include files . . . . . . . . .					. . . . 81
	Check for this . . . . . . . . . . . . . . . . . . . . . . . . . .					. . . . 82
	Unmodeled pins . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82
	Check for this . . . . . . . . . . . . . . . . . . . . . . . . . .					. . . . 83
	Missing ground . . . . . . . . . . . . . . . . . . . . . . . . . . .					. . . . 83
	Check for this . . . . . . . . . . . . . . . . . . . . . . . . . .					. . . . 83
	Missing DC path to ground . . . . . . . . . . . . . . . . . . . .					. . . . 84
	Check for this . . . . . . . . . . . . . . . . . . . . . . . . . .					. . . . 84

v

Contents

Chapter 4	Creating and editing models 85
	Chapter overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .			85
	What are models? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .			87
	Models defined as model parameter sets . . . . . . . . . . . . . .			87
	Models defined as subcircuit netlists . . . . . . . . . . . . . . . .			87
	How are models organized? . . . . . . . . . . . . . . . . . . . . . . . . .			88
	Model libraries . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .			88
	Model library configuration . . . . . . . . . . . . . . . . . . . . . . .			89
	Global vs. design models and libraries . . . . . . . . . . . . . . . . .			89
	Nested model libraries . . . . . . . . . . . . . . . . . . . . . . . . . .			90
	OrCAD-provided models . . . . . . . . . . . . . . . . . . . . . . . . .			90
	Tools to create and edit models . . . . . . . . . . . . . . . . . . . . . . . .			91
	Ways to create and edit models . . . . . . . . . . . . . . . . . . . . . . . .			92
	Using the Model Editor to
	edit models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .			93
	Ways to use the Model Editor . . . . . . . . . . . . . . . . . . . . . .			94
	Model Editor-supported device types . . . . . . . . . . . . . . . . . .			95
	Ways To Characterize Models . . . . . . . . . . . . . . . . . . . . . .			96
	Creating models from data sheet information . . . . . . . . . . .			96
	Analyzing the effect of model parameters
	on device characteristics . . . . . . . . . . . . . . . . . . .			97
	How to fit models . . . . . . . . . . . . . . . . . . . . . . . . . . . . .			97
	Running the Model Editor alone . . . . . . . . . . . . . . . . . . . . .			99
	Starting the Model Editor . . . . . . . . . . . . . . . . . . . . . . .			99
	Enabling and disabling automatic part creation		. . . . . . . . . . 100
	Saving global models (and parts)	. . . . . . . . . . . . . . . . . . 100
	Running the Model Editor from the schematic page editor . . . . . . 101
	What is an instance model? . . . . . . . . . . . . . . . . . . . . . . 101
	Starting the Model Editor . . . . . . . . . . . . . . . . . . . . . . . 102
	Saving design models . . . . . . . . . . . . . . . . . . . . . . . . . 102
	What happens if you don’t save the instance model . . . . . . . . 103
	The Model Editor tutorial . . . . . . . . . . . . . . . . . . . . . . . . . 104
	Creating the half-wave rectifier design . . . . . . . . . . . . . . . 104
	Using the Model Editor to edit the D1 diode model . . . . . . . . 105
	Entering data sheet information	. . . . . . . . . . . . . . . . . . . 105
	Extracting model parameters . . . . . . . . . . . . . . . . . . . . . 107
	Adding curves for more than one temperature		. . . . . . . . . . 108
	Completing the model definition	. . . . . . . . . . . . . . . . . . 109
	Editing model text . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .			110
	Editing .MODEL definitions . . . . . . . . . . . . . . . . . . . . .			110
	Editing .SUBCKT definitions . . . . . . . . . . . . . . . . . . . . .			111

vi

Contents

	Changing the model name . . . . . . . . . . . . . . . . . . . . . .	111
	Starting the Model Editor
	from the schematic page editor in Capture . . . . . . . . . .	111
	What is an instance model? . . . . . . . . . . . . . . . . . . . . .	112
	Starting the Model Editor . . . . . . . . . . . . . . . . . . . . . .	112
	Saving design models . . . . . . . . . . . . . . . . . . . . . . . .	113
	Example: editing a Q2N2222 instance model . . . . . . . . . . . . . .	114
	Starting the Model Editor . . . . . . . . . . . . . . . . . . . . . .	114
	Editing the Q2N2222-X model instance . . . . . . . . . . . . . .	114
	Saving the edits and updating the schematic . . . . . . . . . . .	115
	Using the Create Subcircuit command . . . . . . . . . . . . . . . . . . .	115
	Changing the model reference to an existing model definition . . . . . . 117
	Reusing instance models . . . . . . . . . . . . . . . . . . . . . . . . . . .	118
	Reusing instance models in the same schematic . . . . . . . . . . . .	118
	Making instance models available to all designs . . . . . . . . . . .	119
	Configuring model libraries . . . . . . . . . . . . . . . . . . . . . . . . .	120
	The Libraries and Include Files tabs . . . . . . . . . . . . . . . . . . .	120
	How PSpice uses model libraries . . . . . . . . . . . . . . . . . . . .	121
	Search order . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	121
	Handling duplicate model names . . . . . . . . . . . . . . . . . .	122
	Adding model libraries to the configuration . . . . . . . . . . . . . .	122
	Changing design and global scope . . . . . . . . . . . . . . . . . . .	123
	Changing model library search order . . . . . . . . . . . . . . . . . .	124
	Changing the library search path . . . . . . . . . . . . . . . . . . . .	125
Chapter 5	Creating parts for models 127
	Chapter overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	127
	What’s different about parts used for simulation? . . . . . . . . . . . . .	129
	Ways to create parts
	for models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	129
	Preparing your models for part creation . . . . . . . . . . . . . . . . . .	130
	Using the Model Editor to create parts . . . . . . . . . . . . . . . . . . .	131
	Starting the Model Editor . . . . . . . . . . . . . . . . . . . . . . . . .	131
	Setting up automatic part creation . . . . . . . . . . . . . . . . . . .	132
	Basing new parts on a custom set of parts . . . . . . . . . . . . . . . . .	133
	Editing part graphics . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	135
	How Capture places parts . . . . . . . . . . . . . . . . . . . . . . . .	135
	Defining grid spacing . . . . . . . . . . . . . . . . . . . . . . . . . . .	136
	Grid spacing for graphics . . . . . . . . . . . . . . . . . . . . . .	136
	Grid spacing for pins . . . . . . . . . . . . . . . . . . . . . . . . .	136
	Attaching models to parts . . . . . . . . . . . . . . . . . . . . . . . . . .	138

vii

Contents

	MODEL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 138
	Defining part properties needed for simulation		. . . . . . . . . . . . . . 139
	PSPICETEMPLATE . . . . . . . . . . . . . . . . . . . . . . . . . . . .				140
	PSPICETEMPLATE syntax . . . . . . . . . . . . . . . . . . . . . . 140
	PSPICETEMPLATE examples . . . . . . . . . . . . . . . . . . . . 143
Chapter 6	Analog behavioral modeling 147
	Chapter overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .				147
	Overview of analog behavioral modeling . . . . . . . . . . . . . . . . . . 148
	The ABM.OLB part library file . . . . . . . . . . . . . . . . . . . . . . . .				149
	Placing and specifying ABM parts . . . . . . . . . . . . . . . . . . . . . . 150
	Net names and device names in ABM expressions			. . . . . . . . . . 150
	Forcing the use of a global definition . . . . . . . . . . . . . . . . . .				151
	ABM part templates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .				152
	Control system parts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 153
	Basic components . . . . . . . . . . . . . . . . . . . . . . . . . . . . .				155
	Limiters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .				156
	Chebyshev filters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 157
	Integrator and differentiator . . . . . . . . . . . . . . . . . . . . . . .				160
	Table look-up parts . . . . . . . . . . . . . . . . . . . . . . . . . . . .				160
	Laplace transform part . . . . . . . . . . . . . . . . . . . . . . . . . .				164
	Math functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 167
	ABM expression parts . . . . . . . . . . . . . . . . . . . . . . . . . .				168
	An instantaneous device example: modeling a triode . . . . . . . . . 171
	PSpice-equivalent parts . . . . . . . . . . . . . . . . . . . . . . . . . . . .				174
	Implementation of PSpice -equivalent parts		. . . . . . . . . . . . . . 175
	Modeling mathematical or instantaneous relationships . . . . . . . . 176
	EVALUE and GVALUE parts	. . . . . . . . . . . . . . . . . . . . 176
	EMULT, GMULT, ESUM, and GSUM . . . . . . . . . . . . . . . . 178
	Lookup tables (ETABLE and GTABLE) . . . . . . . . . . . . . . . . . 179
	Frequency-domain device models . . . . . . . . . . . . . . . . . . . . 181
	Laplace transforms (LAPLACE)	. . . . . . . . . . . . . . . . . . . . . 181
	Frequency response tables (EFREQ and GFREQ)			. . . . . . . . . . . 183
	Cautions and recommendations for simulation and analysis . . . . . . . 186
	Instantaneous device modeling	. . . . . . . . . . . . . . . . . . . . . 186
	Frequency-domain parts . . . . . . . . . . . . . . . . . . . . . . . . .				187
	Laplace transforms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 187
	Non-causality and Laplace transforms		. . . . . . . . . . . . . . . 188
	Chebyshev filters . . . . . . . . . . . . . . . . . . . . . . . . . . .				190
	Frequency tables . . . . . . . . . . . . . . . . . . . . . . . . . . . . 190
	Trading off computer resources for accuracy . . . . . . . . . . . . . . 191

viii

Contents

	Basic controlled sources . . . . . . . . . . . . . . . . . . . . . . . . . . . .		192
	Creating custom ABM parts . . . . . . . . . . . . . . . . . . . . . . .		192
Part three	Setting Up and Running Analyses
Chapter 7	Setting up analyses and starting simulation 195
	Chapter overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .		195
	Analysis types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .		196
	Setting up analyses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .		197
	Execution order for standard analyses . . . . . . . . . . . . . . . . .		198
	Output variables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .		199
	Modifiers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .		200
	Starting a simulation . . . . . . . . . . . . . . . . . . . . . . . . . . . . .		206
	Starting a simulation from Capture . . . . . . . . . . . . . . . . . . .		206
	Starting a simulation outside of Capture . . . . . . . . . . . . . . . .		207
	Setting up batch simulations . . . . . . . . . . . . . . . . . . . . . . .		207
	Multiple simulation setups within one circuit file . . . . . . . . .		207
	Running simulations with multiple circuit files . . . . . . . . . .		208
	The PSpice simulation window . . . . . . . . . . . . . . . . . . . . .		208
Chapter 8	DC analyses	213
	Chapter overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .		213
	DC Sweep . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .		214
	Minimum requirements to run a DC sweep analysis . . . . . . . . .		214
	Overview of DC sweep . . . . . . . . . . . . . . . . . . . . . . . . . .		216
	Setting up a DC stimulus . . . . . . . . . . . . . . . . . . . . . . . . .		218
	Nested DC sweeps . . . . . . . . . . . . . . . . . . . . . . . . . . . .		219
	Curve families for DC sweeps . . . . . . . . . . . . . . . . . . . . . .		221
	Bias point . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .		223
	Minimum requirements to run a bias point analysis . . . . . . . . .		223
	Overview of bias point . . . . . . . . . . . . . . . . . . . . . . . . . .		223
	Small-signal DC transfer . . . . . . . . . . . . . . . . . . . . . . . . . . .		225
	Minimum requirements to run a small-signal DC transfer analysis . 225
	Overview of small-signal DC transfer . . . . . . . . . . . . . . . . . .		226
	DC sensitivity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .		228
	Minimum requirements to run a DC sensitivity analysis . . . . . . .		228
	Overview of DC sensitivity . . . . . . . . . . . . . . . . . . . . . . . .		229
Chapter 9	AC analyses	231
	Chapter overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .		231

ix

Contents

	AC sweep analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 232
	Setting up and running an AC sweep		. . . . . . . . . . . . . . . . . . 232
	What is AC sweep? . . . . . . . . . . . . . . . . . . . . . . . . . . . .				232
	Setting up an AC stimulus . . . . . . . . . . . . . . . . . . . . . . . .				233
	Setting up an AC analysis . . . . . . . . . . . . . . . . . . . . . . . . . 235
	AC sweep setup in example.opj	. . . . . . . . . . . . . . . . . . . . . 237
	How PSpice treats nonlinear devices		. . . . . . . . . . . . . . . . . . 239
	What’s required to transform a device into a linear circuit . . . . 239
	What PSpice does . . . . . . . . . . . . . . . . . . . . . . . . . . .				239
	Example: nonlinear behavioral modeling block . . . . . . . . . . 239
	Noise analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 241
	Setting up and running a noise analysis . . . . . . . . . . . . . . . . . 241
	What is noise analysis? . . . . . . . . . . . . . . . . . . . . . . . . . .				242
	How PSpice calculates total output
	and input noise . . . . . . . . . . . . . . . . . . . . . . . .				242
	Setting up a noise analysis . . . . . . . . . . . . . . . . . . . . . . . .				243
	Analyzing Noise in the Probe window		. . . . . . . . . . . . . . . . . 245
	About noise units . . . . . . . . . . . . . . . . . . . . . . . . . . .				246
	Example . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 246
Chapter 10	Transient analysis 249
	Chapter overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .				249
	Overview of transient analysis . . . . . . . . . . . . . . . . . . . . . . . .				250
	Minimum requirements to run a transient analysis . . . . . . . . . . 250
	Minimum circuit design requirements			. . . . . . . . . . . . . . . 250
	Minimum program setup requirements			. . . . . . . . . . . . . . 250
	Defining a time-based stimulus . . . . . . . . . . . . . . . . . . . . . . .				252
	Overview of stimulus generation	. . . . . . . . . . . . . . . . . . . . 252
	The Stimulus Editor utility . . . . . . . . . . . . . . . . . . . . . . . . . .				253
	Stimulus files . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 253
	Configuring stimulus files . . . . . . . . . . . . . . . . . . . . . . . .				254
	Starting the Stimulus Editor . . . . . . . . . . . . . . . . . . . . . . .				254
	Defining stimuli . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .				256
	Example: piecewise linear stimulus . . . . . . . . . . . . . . . . . 256
	Example: sine wave sweep . . . . . . . . . . . . . . . . . . . . . . 257
	Creating new stimulus symbols	. . . . . . . . . . . . . . . . . . . . . 259
	Editing a stimulus . . . . . . . . . . . . . . . . . . . . . . . . . . . . .				260
	To edit an existing stimulus . . . . . . . . . . . . . . . . . . . . .				260
	To edit a PWL stimulus . . . . . . . . . . . . . . . . . . . . . . . . 260
	To select a time and value scale factor for PWL stimuli . . . . . . 260
	Deleting and removing traces . . . . . . . . . . . . . . . . . . . . . .				261

x

Contents

	Manual stimulus configuration . . . . . . . . . . . . . . . . . . . . .	261
	To manually configure a stimulus . . . . . . . . . . . . . . . . .	261
	Transient (time) response . . . . . . . . . . . . . . . . . . . . . . . . . . .	263
	Internal time steps in transient analyses . . . . . . . . . . . . . . . . . .	265
	Switching circuits in transient analyses . . . . . . . . . . . . . . . . . . .	266
	Plotting hysteresis curves . . . . . . . . . . . . . . . . . . . . . . . . . . .	266
	Fourier components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	268
Chapter 11	Parametric and temperature analysis 271
	Chapter overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	271
	Parametric analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	272
	Minimum requirements to run a parametric analysis . . . . . . . . .	272
	Overview of parametric analysis . . . . . . . . . . . . . . . . . . . .	273
	RLC filter example . . . . . . . . . . . . . . . . . . . . . . . . . . . .	274
	Entering the design . . . . . . . . . . . . . . . . . . . . . . . . . .	274
	Running the simulation . . . . . . . . . . . . . . . . . . . . . . .	275
	Using performance analysis to plot overshoot and rise time . . . 275
	Example: frequency response vs. arbitrary parameter . . . . . . . .	278
	Setting up the circuit . . . . . . . . . . . . . . . . . . . . . . . . .	278
	Temperature analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	281
	Minimum requirements to run a temperature analysis . . . . . . . .	281
	Overview of temperature analysis . . . . . . . . . . . . . . . . . . . .	282
Chapter 12	Monte Carlo and sensitivity/worst-case analyses 283
	Chapter overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	283
	Statistical analyses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	284
	Overview of statistical analyses . . . . . . . . . . . . . . . . . . . . .	284
	Output control for statistical analyses . . . . . . . . . . . . . . . . . .	285
	Model parameter values reports . . . . . . . . . . . . . . . . . . . . .	285
	Waveform reports . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	286
	Collating functions . . . . . . . . . . . . . . . . . . . . . . . . . . . .	287
	Temperature considerations in statistical analyses . . . . . . . . . .	288
	Monte Carlo analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	289
	Reading the summary report . . . . . . . . . . . . . . . . . . . .	291
	Example: Monte Carlo analysis of a pressure sensor . . . . . . . . .	293
	Drawing the schematic . . . . . . . . . . . . . . . . . . . . . . . .	293
	Defining part values . . . . . . . . . . . . . . . . . . . . . . . . .	294
	Setting up the parameters . . . . . . . . . . . . . . . . . . . . . .	295
	Using resistors with models . . . . . . . . . . . . . . . . . . . . .	296
	Saving the design . . . . . . . . . . . . . . . . . . . . . . . . . . .	297
	Defining tolerances for the resistor models . . . . . . . . . . . .	297

xi

Contents

	Setting up the analyses . . . . . . . . . . . . . . . . . . . . . . . .	299
	Running the analysis and viewing the results . . . . . . . . . . . 300
	Monte Carlo Histograms . . . . . . . . . . . . . . . . . . . . . . . . .	301
	Chebyshev filter example . . . . . . . . . . . . . . . . . . . . . . . 301
	Creating models for Monte Carlo analysis . . . . . . . . . . . . . 302
	Setting up the analysis . . . . . . . . . . . . . . . . . . . . . . . .	302
	Creating histograms . . . . . . . . . . . . . . . . . . . . . . . . . . 303
	Worst-case analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	306
	Overview of worst-case analysis . . . . . . . . . . . . . . . . . . . . . 306
	Inputs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 307
	Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 307
	Outputs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 308
	Caution: An important condition for
	correct worst-case analysis . . . . . . . . . . . . . . . . . . 308
	Worst-case analysis example . . . . . . . . . . . . . . . . . . . . . . .	309
	Tips and other useful information . . . . . . . . . . . . . . . . . . . . 313
	VARY BOTH, VARY DEV, and VARY LOT . . . . . . . . . . . . 313
	Gaussian distributions . . . . . . . . . . . . . . . . . . . . . . . .	314
	YMAX collating function . . . . . . . . . . . . . . . . . . . . . . .	314
	RELTOL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	314
	Sensitivity analysis . . . . . . . . . . . . . . . . . . . . . . . . . .	314
	Manual optimization . . . . . . . . . . . . . . . . . . . . . . . . .	314
	Monte Carlo analysis . . . . . . . . . . . . . . . . . . . . . . . . .	315
Part four	Viewing results
Chapter 13	Analyzing waveforms 319
	Chapter overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	319
	Overview of waveform analysis . . . . . . . . . . . . . . . . . . . . . . . 320
	Elements of a plot . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	321
	Elements of a Probe window . . . . . . . . . . . . . . . . . . . . . . . 322
	Managing multiple Probe windows . . . . . . . . . . . . . . . . . . . 323
	Printing multiple windows . . . . . . . . . . . . . . . . . . . . . . 323
	Setting up waveform analysis . . . . . . . . . . . . . . . . . . . . . . . . . 324
	Setting up colors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	324
	Editing display and print colors in the PSPICE.INI file . . . . . . 324
	Configuring trace color schemes . . . . . . . . . . . . . . . . . . . 326
	Viewing waveforms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	327
	Setting up waveform display from Capture . . . . . . . . . . . . . . 327
	Viewing waveforms while simulating . . . . . . . . . . . . . . . . . . 328
	Configuring update intervals . . . . . . . . . . . . . . . . . . . .	329

xii

Contents

	Interacting with waveform analysis during simulation . . . . .	329
	Pausing a simulation and viewing waveforms . . . . . . . . . .	330
	Using schematic page markers to add traces . . . . . . . . . . . . . .	331
	Limiting waveform data file size . . . . . . . . . . . . . . . . . . . .	334
	Limiting file size using markers . . . . . . . . . . . . . . . . . . .	334
	Limiting file size by excluding internal subcircuit data . . . . . . 336
	Limiting file size by suppressing the first part
	of simulation output . . . . . . . . . . . . . . . . . . . . .	336
	Using simulation data from multiple files . . . . . . . . . . . . . . .	337
	Appending waveform data files . . . . . . . . . . . . . . . . . . .	337
	Adding traces from specific loaded waveform data files . . . . . 338
	Saving simulation results in ASCII format . . . . . . . . . . . . . . .	339
	Analog example . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	341
	Running the simulation . . . . . . . . . . . . . . . . . . . . . . .	341
	Displaying voltages on nets . . . . . . . . . . . . . . . . . . . . .	343
	User interface features for waveform analysis . . . . . . . . . . . . . . .	344
	Zoom regions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	344
	Scrolling traces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	346
	Modifying trace expressions and labels . . . . . . . . . . . . . . . . .	346
	Moving and copying trace names and expressions . . . . . . . . . .	347
	Copying and moving labels . . . . . . . . . . . . . . . . . . . . . . .	348
	Tabulating trace data values . . . . . . . . . . . . . . . . . . . . . . .	349
	Using cursors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	350
	Displaying cursors . . . . . . . . . . . . . . . . . . . . . . . . . .	350
	Moving cursors . . . . . . . . . . . . . . . . . . . . . . . . . . . .	351
	Example: using cursors . . . . . . . . . . . . . . . . . . . . . . . .	352
	Tracking simulation messages . . . . . . . . . . . . . . . . . . . . . . . .	354
	Message tracking from the message summary . . . . . . . . . . . . .	354
	The Simulation Message Summary dialog box . . . . . . . . . .	354
	Persistent hazards . . . . . . . . . . . . . . . . . . . . . . . . . . .	355
	Message tracking from the waveform . . . . . . . . . . . . . . . . . .	356
	Trace expressions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	356
	Basic output variable form . . . . . . . . . . . . . . . . . . . . . . . .	357
	Output variable form for device terminals . . . . . . . . . . . . . . .	358
	Analog trace expressions . . . . . . . . . . . . . . . . . . . . . . . . .	364
	Trace expression aliases . . . . . . . . . . . . . . . . . . . . . . .	364
	Arithmetic functions . . . . . . . . . . . . . . . . . . . . . . . . .	364
	Rules for numeric values suffixes . . . . . . . . . . . . . . . . . .	365
Chapter 14	Other output options 367
	Chapter overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	367

xiii

Contents

	Viewing analog results in the PSpice window . . .			. . . . . . . . . . . . 368
	Writing additional results to the PSpice output file			. . . . . . . . . . . . 369
	Generating plots of voltage and current values			. . . . . . . . . . . . 369
	Generating tables of voltage and current values			. . . . . . . . . . . . 370
Appendix A	Setting initial state 373
	Appendix overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .				373
	Save and load bias point . . . . . . . . . . . . . . . . . . . . . . . . . . . . 374
	Save bias point . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .				374
	Load bias point . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 375
	Setpoints . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 376
	Setting initial conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . 378
Appendix B	Convergence and “time step too small errors”		379
	Appendix overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .				379
	Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 380
	Newton-Raphson requirements	. . . . . . . . . . . . . . . . . . . . . 380
	Is there a solution? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 381
	Are the Equations Continuous?	. . . . . . . . . . . . . . . . . . . . . 382
	Are the derivatives correct? . . . . . . . . . . . . . . . . . . . . .				382
	Is the initial approximation close enough?		. . . . . . . . . . . . . . . 383
	Bias point and DC sweep . . . . . . . . . . . . . . . . . . . . . . . . . . .				385
	Semiconductors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .				385
	Switches . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 386
	Behavioral modeling expressions	. . . . . . . . . . . . . . . . . . . . 387
	Transient analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .				388
	Skipping the bias point . . . . . . . . . . . . . . . . . . . . . . . . . .				389
	The dynamic range of TIME . . . . . . . . . . . . . . . . . . . . . . . 389
	Failure at the first time step . . . . . . . . . . . . . . . . . . . . . . . . 390
	Parasitic capacitances . . . . . . . . . . . . . . . . . . . . . . . . . . .				391
	Inductors and transformers . . . . . . . . . . . . . . . . . . . . . . . . 391
	Bipolar transistors substrate junction . . . . . . . . . . . . . . . . . .				392
	Diagnostics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .				393

Index 395

xiv

Figures

Figure 1 User-configurable data files that PSpice reads . . . . . . . . . . . . . . . . 11 Figure 2 Diode clipper circuit. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 Figure 3 Connection points. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 Figure 4 PSpice simulation output window. . . . . . . . . . . . . . . . . . . . . . . 22 Figure 5 Simulation output file. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 Figure 6 DC sweep analysis settings. . . . . . . . . . . . . . . . . . . . . . . . . . . 27 Figure 7 Probe window. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 Figure 8 Clipper circuit with voltage marker on net Out. . . . . . . . . . . . . . . . 29 Figure 9 Voltage at In, Mid, and Out. . . . . . . . . . . . . . . . . . . . . . . . . . . 29 Figure 11 Trace legend with cursors activated. . . . . . . . . . . . . . . . . . . . . . 30 Figure 12 Trace legend with V(Mid) symbol outlined. . . . . . . . . . . . . . . . . . 30 Figure 13 Voltage difference at V(In) = 4 volts. . . . . . . . . . . . . . . . . . . . . . 31 Figure 14 Diode clipper circuit with a voltage stimulus. . . . . . . . . . . . . . . . . 32 Figure 15 Stimulus Editor window. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34 Figure 16 Transient analysis simulation settings. . . . . . . . . . . . . . . . . . . . . 34 Figure 17 Sinusoidal input and clipped output waveforms. . . . . . . . . . . . . . . 35 Figure 18 Clipper circuit with AC stimulus. . . . . . . . . . . . . . . . . . . . . . . . 37 Figure 19 AC sweep and noise analysis simulation settings. . . . . . . . . . . . . . . 38 Figure 20 dB magnitude curves for “gain” at Mid and Out. . . . . . . . . . . . . . . 40 Figure 21 Bode plot of clipper’s frequency response. . . . . . . . . . . . . . . . . . . 41 Figure 22 Clipper circuit with global parameter Rval. . . . . . . . . . . . . . . . . . 42 Figure 23 Parametric simulation settings. . . . . . . . . . . . . . . . . . . . . . . . . . 44 Figure 24 Small signal response as R1 is varied from 100Ω to 10 kΩ . . . . . . . . . . . 45 Figure 25 Small signal frequency response at 100 and 10 kΩ input resistance. . . . 47 Figure 26 Performance analysis plots of bandwidth and gain vs. Rval. . . . . . . . . 50 Figure 27 Relationship of the Model Editor to Capture and PSpice . . . . . . . . . . 93 Figure 28 Process and data flow for the Model Editor. . . . . . . . . . . . . . . . . . 96 Figure 29 Model Editor workspace with data for a bipolar transistor. . . . . . . . . 97 Figure 30 Design for a half-wave rectifier. . . . . . . . . . . . . . . . . . . . . . . . 104 Figure 31 Model characteristics and parameter values for DbreakX. . . . . . . . . 105 Figure 32 Assorted device characteristic curves for a diode. . . . . . . . . . . . . . 108 Figure 33 Forward Current device curve at two temperatures. . . . . . . . . . . . 109

Figures

Figure 34 Rules for pin callout in subcircuit templates. . . . . . . . . . . . . . . . . 146 Figure 35 LOPASS filter example. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 157 Figure 36 HIPASS filter part example. . . . . . . . . . . . . . . . . . . . . . . . . . . 158 Figure 37 BANDPASS filter part example. . . . . . . . . . . . . . . . . . . . . . . . 159 Figure 38 BANDREJ filter part example. . . . . . . . . . . . . . . . . . . . . . . . . 159 Figure 39 FTABLE part example. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 162 Figure 40 LAPLACE part example one. . . . . . . . . . . . . . . . . . . . . . . . . . 165 Figure 41 Viewing gain and phase characteristics of a lossy integrator. . . . . . . . 165 Figure 42 LAPLACE part example two. . . . . . . . . . . . . . . . . . . . . . . . . . 165 Figure 43 ABM expression part example one. . . . . . . . . . . . . . . . . . . . . . 169 Figure 44 ABM expression part example two. . . . . . . . . . . . . . . . . . . . . . 169 Figure 45 ABM expression part example three. . . . . . . . . . . . . . . . . . . . . . 170 Figure 46 ABM expression part example four. . . . . . . . . . . . . . . . . . . . . . 170 Figure 47 Triode circuit. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 171 Figure 48 Triode subcircuit producing a family of I-V curves. . . . . . . . . . . . . 173 Figure 49 EVALUE part example. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 177 Figure 50 GVALUE part example. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 177 Figure 51 EMULT part example. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 178 Figure 52 GMULT part example. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 179 Figure 53 EFREQ part example. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 185 Figure 54 Voltage multiplier circuit (mixer). . . . . . . . . . . . . . . . . . . . . . . 186 Figure 55 PSpice simulation window . . . . . . . . . . . . . . . . . . . . . . . . . . 210 Figure 56 Example schematic EXAMPLE.OPJ. . . . . . . . . . . . . . . . . . . . . . 217 Figure 57 Curve family example schematic. . . . . . . . . . . . . . . . . . . . . . . 221 Figure 58 Device curve family. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 222 Figure 59 Operating point determination for each member of the curve family. . . 222 Figure 60 Circuit diagram for EXAMPLE.OPJ. . . . . . . . . . . . . . . . . . . . . . 237 Figure 61 AC analysis setup for EXAMPLE.OPJ. . . . . . . . . . . . . . . . . . . . . 238 Figure 62 Device and total noise traces for EXAMPLE.DSN. . . . . . . . . . . . . . 247 Figure 63 Transient analysis setup for EXAMPLE.OPJ. . . . . . . . . . . . . . . . . 263 Figure 64 Example schematic EXAMPLE.OPJ. . . . . . . . . . . . . . . . . . . . . . 264 Figure 65 ECL-compatible Schmitt trigger. . . . . . . . . . . . . . . . . . . . . . . . 266 Figure 66 Netlist for Schmitt trigger circuit. . . . . . . . . . . . . . . . . . . . . . . . 267 Figure 67 Hysteresis curve example: Schmitt trigger. . . . . . . . . . . . . . . . . . 268 Figure 68 Passive filter schematic. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 274 Figure 69 Current of L1 when R1 is 1.5 ohms. . . . . . . . . . . . . . . . . . . . . . 276 Figure 70 Rise time and overshoot vs. damping resistance. . . . . . . . . . . . . . . 277 Figure 71 RLC filter example circuit. . . . . . . . . . . . . . . . . . . . . . . . . . . . 278 Figure 72 Plot of capacitance versus bias voltage. . . . . . . . . . . . . . . . . . . . 280 Figure 73 Example schematic EXAMPLE.OPJ. . . . . . . . . . . . . . . . . . . . . . 282 Figure 74 Example schematic EXAMPLE.DSN. . . . . . . . . . . . . . . . . . . . . 288 Figure 75 Monte Carlo analysis setup for EXAMPLE.DSN. . . . . . . . . . . . . . . 290

xvi

Figures

Figure 76 Summary of Monte Carlo runs for EXAMPLE.OPJ. . . . . . . . . . . . . 291 Figure 77 Parameter values for Monte Carlo pass three. . . . . . . . . . . . . . . . 292 Figure 78 Pressure sensor circuit. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 293 Figure 79 Model definition for RMonte1. . . . . . . . . . . . . . . . . . . . . . . . . 298 Figure 80 Pressure sensor circuit with RMonte1 and RTherm model definitions. . 299 Figure 81 Chebyshev filter. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 302 Figure 82 1 dB bandwidth histogram. . . . . . . . . . . . . . . . . . . . . . . . . . . 305 Figure 83 Center frequency histogram. . . . . . . . . . . . . . . . . . . . . . . . . . 306 Figure 84 Simple biased BJT amplifier. . . . . . . . . . . . . . . . . . . . . . . . . . 309 Figure 85 Amplifier netlist and circuit file. . . . . . . . . . . . . . . . . . . . . . . . 310 Figure 86 YatX Goal Function. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 311 Figure 87 Correct worst-case results. . . . . . . . . . . . . . . . . . . . . . . . . . . 312 Figure 88 Incorrect worst-case results. . . . . . . . . . . . . . . . . . . . . . . . . . 312 Figure 89 Schematic using VARY BOTH. . . . . . . . . . . . . . . . . . . . . . . . . 313 Figure 90 Circuit file using VARY BOTH. . . . . . . . . . . . . . . . . . . . . . . . 313 Figure 91 Analog and digital areas of a plot. . . . . . . . . . . . . . . . . . . . . . . 321 Figure 92 Two Probe windows. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 322 Figure 93 Trace legend symbols. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 338 Figure 94 Section information message box. . . . . . . . . . . . . . . . . . . . . . . 339 Figure 95 Example schematic EXAMPLE.OPJ. . . . . . . . . . . . . . . . . . . . . . 341 Figure 96 Waveform display for EXAMPLE.DAT. . . . . . . . . . . . . . . . . . . 342 Figure 97 Cursors positioned on a trough and peak of V(1) . . . . . . . . . . . . . 352 Figure 98 Waveform display for a persistent hazard. . . . . . . . . . . . . . . . . . 355 Figure A-1 Setpoints. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 376

xvii

Figures

xviii

Tables

Table 1	DC analysis types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .		3
Table 2	AC analysis types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .		4
Table 3	Time-based analysis types . . . . . . . . . . . . . . . . . . . . . . . . . . .		5
Table 4	Parametric and temperature analysis types . . . . . . . . . . . . . . . . . .		6
Table 5	Statistical analysis types . . . . . . . . . . . . . . . . . . . . . . . . . . . . .		7
Table 2-1			25
Table 10	Association of cursors with mouse buttons. . . . . . . . . . . . . . . . . . 30
Table 2-1			31
Table 2-1			36
Table 2-2			41
Table 2-3			48
Table 2-4			51
Table 5			58
Table 6			59
Table 7	Passive parts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .		64
Table 8	Breakout parts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .		65
Table 9	Operators in expressions . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70
Table 10	Functions in arithmetic expressions . . . . . . . . . . . . . . . . . . . . . . 71
Table 11	System variables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73
Table 12			74
Table 13			75
Table 14			77
Table 15			78
Table 16			80
Table 17	Models supported in the Model Editor . . . . . . . . . . . . . . . . . . . 95
Table 1	Sample diode data sheet values . . . . . . . . . . . . . . . . . . . . . . .	106
Table 2	Part names for custom part generation. . . . . . . . . . . . . . . . . . . .	133
Table 3		139
Table 4		141
Table 5		142
Table 6		145
Table 7	Control system parts . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	153

Tables

Table 1	ABM math function parts . . . . . . . . . .				. . . . . . . . . . . . . . . . . 167
Table 2	ABM expression parts . . . . . . . . . . . .				. . . . . . . . . . . . . . . . . 168
Table 1	PSpice -equivalent parts . . . . . . . . . .				. . . . . . . . . . . . . . . . . 174
Table 1	Basic controlled sources in ANALOG.OLB				. . . . . . . . . . . . . . . . . 192
Table 2	Classes of PSpice analyses	. . . . . . . . . . . . . . . . . . . . . . . . . . 196
Table 3	Execution order for standard analyses . . . . . . . . . . . . . . . . . . . . 198
Table 4	PSpice output variable formats		. . . . . . . . . . . . . . . . . . . . . . . 201
Table 5	Element definitions for 2-terminal devices				. . . . . . . . . . . . . . . . . 202
Table 6	Element definitions for 3- or 4-terminal devices					. . . . . . . . . . . . . . 203
Table 7	Element definitions for transmission line devices					. . . . . . . . . . . . . 204
Table 8	Element definitions for AC analysis specific elements . . . . . . . . . . 205
Table 9	DC sweep circuit design requirements			. . . . . . . . . . . . . . . . . . . 214
Table 10						218
Table 11						218
Table 12						219
Table 1	Curve family example setup . . . . . . . . . . . . . . . . . . . . . . . . . 221
Table 2						233
Table 3						233
Table 4						234
Table 5						234
Table 6						236
Table 7						242
Table 8						244
Table 9						246
Table 10	Stimulus symbols for time-based input signals					. . . . . . . . . . . . . . 252
Table 1	Parametric analysis circuit design requirements					. . . . . . . . . . . . . . 272
Table 1	Collating functions used in statistical analyses . . . . . . . . . . . . . . . 287
Table 1						294
Table 2						295
Table 3						300
Table 1	Default waveform viewing colors. . . . . . . . . . . . . . . . . . . . . . . 325
Table 2						326
Table 3						328
Table 4						330
Table 5						332
Table 6						333
Table 1						346
Table 2	Mouse actions for cursor control		. . . . . . . . . . . . . . . . . . . . . . . 351
Table 3	Key combinations for cursor control			. . . . . . . . . . . . . . . . . . . . 351
Table 4						357
Table 5						358
Table 6	Output variable formats	. . . . . . . . . . . . . . . . . . . . . . . . . . . 358

xx

		Tables
Table 7	Examples of output variable formats . . . . . . . . . . . . . . . . . . . .	360
Table 8	Output variable AC suffixes . . . . . . . . . . . . . . . . . . . . . . . . .	361
Table 9	Device names for two-terminal device types . . . . . . . . . . . . . . .	361
Table 10	Terminal IDs by three & four-terminal device type . . . . . . . . . . . .	362
Table 11	Noise types by device type . . . . . . . . . . . . . . . . . . . . . . . . . .	363
Table 12	Analog arithmetic functions for trace expressions . . . . . . . . . . . .	364
Table 13	Output units for trace expressions . . . . . . . . . . . . . . . . . . . . .	366
Table 14		369
Table 15		370

xxi

Tables

xxii

Before you begin

Welcome to OrCAD

OrCAD® offers a total solution for your core design tasks: schematicand VHDL-based design entry; FPGA and CPLD design synthesis; digital, analog, and mixed-signal simulation; and printed circuit board layout. What's more, OrCAD's products are a suite of applications built around an engineer's design flow--not just a collection of independently developed point tools. PSpice is just one element in OrCAD's total solution design flow.

With OrCAD’s products, you’ll spend less time dealing with the details of tool integration, devising workarounds, and manually entering data to keep files in sync. Our products will help you build better products faster, and at lower cost.

Before you begin

OrCAD PSpice overview

OrCAD PSpice simulates analog-only circuits. After you prepare a design for simulation, OrCAD Capture generates a circuit file set. The circuit file set, containing the circuit netlist and analysis commands, is read by PSpice for simulation. PSpice formulates these into meaningful graphical plots, which you can mark for display directly from your schematic page using markers.

xxiv

How to use this guide

How to use this guide

This guide is designed so you can quickly find the information you need to use PSpice.

This guide assumes that you are familiar with Microsoft Windows (NT or 95), including how to use icons, menus, and dialog boxes. It also assumes you have a basic understanding about how Windows manages applications and files to perform routine tasks, such as starting applications, and opening and saving your work. If you are new to Windows, please review your Microsoft Windows User’s Guide.

Typographical conventions

Before using PSpice, it is important to understand the terms and typographical conventions used in this documentation.

This guide generally follows the conventions used in the

Microsoft Windows User’s Guide. Procedures for performing an operation are generally numbered with the following typographical conventions..

Notation	Examples	Description
C+r	Press C+r	A specific key or key
		stroke on the keyboard.
monospace	Type VAC....	Commands/text entered
font		from the keyborad.

xxv

Before you begin

Related documentation

Documentation for OrCAD products is available in both printed and online forms. To access an online manual instantly, you can select it from the Help menu in its respective program (for example, access the Capture User’s Guide from the Help menu in Capture).

	Note	The documentation you receive depends on the software
		configuration you have purchased.
	The following table provides a brief description of those
	manuals available in both printed and online forms.
This manual...	Provides information about how to use...
OrCAD Capture	OrCAD Capture, which is a schematic capture front-end program
User’s Guide	with a direct interface to other OrCAD programs and options.
OrCAD Layout	OrCAD Layout, which is a PCB layout editor that lets you specify
User’s Guide	printed circuit board sturcture, as well as the components, metal,
	and graphics required for fabrication.
OrCAD PSpice & Basics	PSpice with Probe, the Stimulus Editor, and the Model Editor,
User’s Guide	which are circuit analysis programs that let you create, simulate,
	and test analog and digital circuit designs. This manual provides
	examples on how to specify simulation parameters, analyze
	simulation results, edit input signals, and create models. (PSpice
	Basics is a limited version that does not include the Stimulus
	Editor.)
OrCAD PSpice	OrCAD PSpice with Probe is a circuit analysis program that lets
User’s Guide	you create, simulate, and test analog-only circuit designs.
	.
OrCAD PSpice Optimizer	OrCAD PSpice Optimizer, which is an analog performance
User’s Guide	optimization program that lets you fine-tune your analog circuit
	designs.

The following table provides a brief description of those manuals available online only.

xxvi

	Related documentation
This online manual...	Provides this...
OrCAD PSpice	Reference material for PSpice. Also included: detailed descriptions of the
Online Reference Manual	simulation controls and analysis specifications, start-up option
	definitions, and a list of device types in the analog and digital model
	libraries. User interface commands are provided to instruct you on each
	of the screen commands.
OrCAD Application Notes	A variety of articles that show you how a particular task can be
Online Manual	accomplished using OrCAD’s products, and examples that demonstrate
	a new or different approach to solving an engineering problem.
OrCAD PSpice Library List	A complete list of the analog and digital parts in the model and part
	libraries.

Online Help

Choosing Search for Help On from the Help menu displays an extensive online help system.

The online help includes:

∙step-by-step instructions on how to set up PSpice simulations and analyze simulation results

∙reference information about PSpice

∙Technical Support information

If you are not familiar with Windows (NT or 95) Help system, choose How to Use Help from the Help menu.

xxvii

Before you begin

If you have the demo CD-ROM

OrCAD demo CD-ROM

The OrCAD demo CD-ROM has the following limitations for PSpice:

∙circuit simulation limited to circuits with up to 64 nodes, 10 transistors, two operational amplifiers or 65 digital primitive devices, and 10 transmission lines (ideal or non-ideal) with not more than 4 pairwise coupled lines

∙device characterization using the Model Editor limited to diodes

∙stimulus generation limited to sine waves (analog) and clocks (digital)

∙sample library of approximately 39 analog and 134 digital parts

∙displays only simulation data created using the demo version of the simulator

∙PSpice Optimizer limited to one goal, one parameter and one constraint

∙designs created in Capture can be saved if they have no more than 30 part instances

xxviii

What’s New

What’s New

New PSpice interface with integrated waveform analysis functionality Release 9 of PSpice includes all

of Probe’s features and adds to them. Included in one screen are tabbed windows for viewing plots, text windows for viewing output files or other text files, and a simulation status and message window. Also included is a new, self-documenting analysis setup dialog for creating simulation profiles (see below). PSpice now provides an editable simulation queue which shows you how many files are currently in line to be simulated. You can edit or re-order the list as needed. And the plotting features have been improved by providing user-controlled grid settings, grid and trace properties (style and color) and metafile format copy and paste functions.

Simulation profiles PSpice Release 9 introduces the concept of simulation profiles. Each simulation profile refers to one schematic in a design and includes one analysis type (AC, DC, or Transient) with any options (sensitivity, temperature, parametric, Monte Carlo, etc.). You can define as many profiles as you need for your design and you can set up multiple analyses of the same type. Simulation profiles help you keep your analysis results separate, so you can delete one without losing the rest.

New OrCAD Capture front-end Release 9 integrates OrCAD Capture as the front-end schematic entry tool for PSpice. Capture provides a professional design entry environment with many advanced capabilities that now work hand-in-hand with PSpice. These include a project manager, a new property editor spreadsheet, right mouse button support, and many other time-saving features.

To find out more, see Analyzing waveforms on page -319.

xxix

Before you begin

To find out more, see Creating and editing models on page -85.

New Model Editor interface The Model Editor (formerly known as Parts) has been improved and modernized for Release 9. It now provides a unified application for editing models either in text form or by modifying their specifications. The Model Editor now also supports Darlington modeling.

To find out more, refer to MOSFET devices in the A nalog Devices chapter of the online OrCA D PSpice A /D Reference Manual.

EKV version 2.6 MOSFET model The EKV model is a scalable and compact model built on fundamental physical properties of the device. Use this model to design low-voltage, low-current analog, and mixed analogdigital circuits that use sub-micron technologies.

Version 2.6 models the following:

∙geometrical and process related aspects of the device (oxide thickness, junction depth, effective channel length and width, and so on)

∙effects of doping profile and substrate effects

∙weak, moderate, and strong inversion behavior

∙mobility effects due to vertical and lateral fields and carrier velocity saturation

∙short-channel effects such as channel-length modulation, source and drain charge sharing, and the reverse short channel effect

∙thermal and flicker noise modeling

∙short-distance geometry and bias-dependent device matching for Monte Carlo analysis

Enhanced model libraries The model libraries supplied with PSpice Release 9 have been enhanced to include the latest models from various vendors, as well as models for popular optocouplers, Darlingtons, and DAC and ADC devices.

xxx