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Computer Aided Design
Course 2
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Spice
Simulation
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Common File Extensions
.OPJ Capture project file
.MNL Layout netlist file
.DSN Capture design file
.SWP Layout backannotation file
.OLB Capture part library file
.XRF Cross-reference report
.UPD Property update file
.NET or .ASC Other netlist files
.DRC Design rules check file
.VHD or .VHO VHDL source file
.BOM Bill of Materials file
.EDF EDIF 2.0 netlist
.EXP Export properties file
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Project Manager Window
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Schematics Editing steps
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Start a new project, select “Analog or
Mixed A/D” (enables PSpice)
Create a new directory to hold the files
and provide a descriptive file name
Create the project
Add the PSpice library (ex.
“analog.olb”)
Build and wire the circuit
Annotate
Run Design Rules Check (DRC)
Build Bill of Materials (BOM)
Print
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Automatic Reference Designator Assignment
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Design Rules Check
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Create BOM to List Footprints
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PSpice Analysis Flow
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New Simulation Profile
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Simulation Settings Menu
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Bias Point Display
Enable bias voltage display
Enable power display
Enable bias currents display
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BASIC PART ABBREVIATIONS
Resistor
R
capacitor
C
current-controlled current source
F
current-controlled voltage source
H
ground, analog
AGND
voltage-controlled current source
G
voltage-controlled voltage source
E
Simple voltage source
VAC
Transient sine voltage source
VSIN
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Analog stimuli
The analog stimuli symbols available in Schematics are:
If you want this kind of input... Use this symbol for voltage...
For DC analyses
DC bias
VDC or VSRC
For AC analyses
AC magnitude and phase
VAC or VSRC
For transient analyses
exponential
VEXP or VSTIM*
periodic pulse
VPULSE or VSTIM*
piecewise-linear
VPWL or VSTIM*
VPWL_RE_FOREVER or
piecewise-linear that repeats forever
VPWL_F_RE_FOREVER**
piecewise-linear that repeats n times
VPWL_N_TIMES or VPWL_F_N_TIMES**
frequency-modulated sine wave
VSFFM or VSTIM*
sine wave
VSIN or VSTIM*
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*. VSTIM and ISTIM symbols require the Stimulus Editor to
define the input signal.
**. FILE-BASED Symbols: VPWL_F_RE_FOREVER and
VPWL_F_N_TIMES are file-based symbols; the stimulus
specification resides in a file and adheres to PSpice netlist syntax.
To determine the symbol name for an equivalent Current source
-In the table of voltage source symbols, replace the first V in the
symbol name with I (Example: VDC -> IDC).
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Stimulus Symbols for Analog Time-Based Input Signals
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Defining Stimulus Symbol Attributes Manually in
Schematics
To use any of these source types, you must place the symbol in your
schematic
and
then
define
its
transient
behavior.
Each attribute-characterized stimulus has a distinct set of attributes
depending upon the kind of transient behavior it represents.
For VPWL_F_xxx and IPWL_F_xxx, a separate file contains the
stimulus specification. Defining VSTIM or ISTIM using the Stimulus
Editor
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As an alternative, the Stimulus Editor utility automates the process of
defining the transient behavior of stimulus devices.
The Stimulus Editor allows you to create analog stimuli which generate
sine wave, repeating pulse, exponential pulse, single-frequency FM,
and piecewise linear waveforms. It also facilitates creating digital
stimuli with complex timing relations.
This applies to both stimulus symbols placed in your schematic as well
as new ones that you might create.
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Stimulus Editor
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HOW DOES SPICE WORK?
Basically, SPICE operates like this:
1. Describe a circuit in a text file (“.cir” extension) called a netlist
OR draw the circuit using graphical symbols on a schematic page.
2. Run a simulation. SPICE reads the netlist and then performs the
requested analysis: AC, DC, or TRANSIENT RESPONSE. The results
are stored in a text output file (“.out” extension) or a binary data
file.
3. View the results of the simulation in a text output file ( “.out” )
using a text editor. Most SPICE programs provide a graphical viewer
to plot the waveforms stored in the binary data file (Probe
window).
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Netlist File
R1
* source CIRC1
L1
1
1k
2
V_V1
10uH
C1
1n
V1
VOFF = 0
VAMPL = 1
FREQ = 1k
0
N00129 0
+SIN 0 1 1k 0 0 0
R_R1
1k
N00129 N00138
L_L1
10uH
N00138 N00145
C_C1
0 N00145 1n
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NETLIST OR SCHEMATIC PAGE?
Although, the schematic capture has its advantages, each
SPICE vendor has a different drawing interface and file
format.
This would cause great confusion if you used a version of
SPICE different from the one used at this site.
Also, the learning curve for the schematic capture can be
steep. Many component characteristics are not visible from
the schematic. (Ultimately, the schematic capture program
creates a netlist before running a simulation.)
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NETLIST OR SCHEMATIC PAGE?
The netlist description of a circuit is simple and fairly
consistent for each SPICE vendor with some variations.
The entire circuit and component properties are visible.
Learning the netlist is easy and making changes is fast. You
can create a netlist by drawing the circuit on paper and
applying a few simple rules.
(Several books written on SPICE strongly recommend
learning the netlist, even if you decide later to use a
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schematic capture program.)
NETLIST
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NETLIST
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Output File
**** 03/05/06 16:06:27 ******* PSpice 10.3.0 (Jan 2004) ******* ID# 1111111111
** Profile: "SCHEMATIC1-circ1" [ C:\ORCAD_DATA\CAD\circ1-PSpiceFiles\SCHEMATIC1\circ1.sim ]
****
CIRCUIT DESCRIPTION
******************************************************************************
** Creating circuit file "circ1.cir"
** WARNING: THIS AUTOMATICALLY GENERATED FILE MAY BE OVERWRITTEN BY SUBSEQUENT
SIMULATIONS
*Libraries:
* Profile Libraries :
* Local Libraries :
* From [PSPICE NETLIST] section of C:\OrCAD\OrCAD_10.3\tools\PSpice\PSpice.ini file:
.lib "nom.lib"
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Output File - 2
*Analysis directives:
.TRAN 0 10ms 0
.PROBE V(alias(*)) I(alias(*)) W(alias(*)) D(alias(*)) NOISE(alias(*))
.INC "..\SCHEMATIC1.net"
**** INCLUDING SCHEMATIC1.net ****
* source CIRC1
V_V1
N00129 0
+SIN 0 1 1k 0 0 0
R_R1
N00129 N00138 1k
L_L1
N00138 N00145 10uH
C_C1
0 N00145 1n
**** RESUMING circ1.cir ****
.END
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Output File - 3
**** 03/05/06 16:06:27 ******* PSpice 10.3.0 (Jan 2004) ******* ID# 1111111111
** Profile: "SCHEMATIC1-circ1" [ C:\ORCAD_DATA\CAD\circ1-PSpiceFiles\SCHEMATIC1\circ1.sim ]
****
INITIAL TRANSIENT SOLUTION
TEMPERATURE = 27.000 DEG C
******************************************************************************
NODE VOLTAGE
(N00129)
NODE VOLTAGE
0.0000 (N00138)
NODE VOLTAGE
0.0000 (N00145)
NODE VOLTAGE
0.0000
VOLTAGE SOURCE CURRENTS
NAME
CURRENT
V_V1
0.000E+00
TOTAL POWER DISSIPATION 0.00E+00 WATTS
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Output File - 4
JOB CONCLUDED
**** 03/05/06 16:06:27 ******* PSpice 10.3.0 (Jan 2004) ******* ID# 1111111111
** Profile: "SCHEMATIC1-circ1" [ C:\ORCAD_DATA\CAD\circ1-PSpiceFiles\SCHEMATIC1\circ1.sim ]
****
JOB STATISTICS SUMMARY
******************************************************************************
Total job time (using Solver 1) =
.19
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Probe window
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Probe window
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Probe window
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Probe window
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