PSPICE FOR DUMMIES



PSPICE MANUAL

INTRODUCTION 2

THE FIRST STEPS 2

USING NETLIST 3

USING SCHEMATIC CAPTURE 3

ERRORS AND WARNINGS 4

NAVIGATING PROBE 5

SHORTCUTS 6

REFERENCES OF PARAMETERS 7

INTRODUCTION TO THE PSPICE MANUAL

Welcome to SPICEWORLD.. PSPICE , that is. This mini manual was constructed to help facilitate the process of executing lab work (and to cut down on overbearing the Lab Assistant with the same questions, especially when there are a few dozen of YOU and only one of them). The odds are that you are an Electrical Engineering student, and if you are, then PSPICE is your friend! In other words, there’s a good chance (especially if your emphasis is circuit design or solid state electronics) that you will be seeing more SPICE in other classes as you continue your education as an undergrad, graduate level and even in INDUSTRY; so it’s best to look at the application in a positive light instead of dreading it’s usage.

This was written for the Evaluation or Release 8 version, but over 90% of the material should be valid for versions 6 and 7.

THE FIRST STEPS:

Before you even open the application, you should construct what could be called a “default file” or folder on the Desktop (or anywhere else you wish). The reason being is that as you do several simulations, you will accumulate a numerous amount of files wherever you save them to, and the file construction would be good for housekeeping. If there’s no space on the hard-drive to save the files to.. BUMMER, you have to save and simulate them on a floppy and this means longer time for simulation, but oh well.. now let’s get started; from the “Start” button on the bottom tool bar go to the PSPICE application and then:

1. Choose “Schematics” on the tool bar

2. Go to “File” and choose “New” (the next two steps are important)

3. Go to “File” again and choose “Save As” , name and save your schematic (in your default file)

4. Go to “Analysis” and choose “Create Netlist”

Congratulations, you are now ready to make a circuit. You can either use Netlist or Schematic Capture. It is strongly suggested that you master both techiques!

USING NETLIST

If you use Netlist, go to “Analysis” again (after Step 4, see FIRST STEPS above) and choose “Examine Netlist” . This will pull up the text editor with the top line reading: *Schematics Netlist*

You can now enter your parameters under this line. Relax, you have seen this (and done this) before from your previous Networks classes. If the lab manual has parameters to be followed, then be sure to add them in the proper place in your Netlist code or you may get the undesired and/or the incorrect output in PROBE. After you edit and you are ready to simulate, you must SAVE IT FIRST! You can go to “File” and choose “Save” or you can use Ctrl+S on the keyboard (see SHORTCUTS). Once saved, then you can simulate; this can be done by getting out of the Editor and back to the Schematics screen, go to “Analysis” and then choose “Simulate”. You can just as well use the F11 key (see SHORTCUTS).

USING SCHEMATIC CAPTURE

To pick an element for your schematic, you must go to “Draw” on the upper tool bar and choose “Get New Part”. From the Part Browser screen click the arrow key to the space under “Description Search” and type in the part that you would like to use for your schematic; then click on the “Search” button or hit the “Return” key on the keyboard. From the lower left window, click the desired element, and then click on either the “Place” or the “Place & Close” button. To place the element on the schematic, just click where you want it placed; hit the “Esc” on the keyboard to discontinue the use of the element. To connect the elements, you can go to “Draw” then choose “Wire”, or you can use Ctrl+W from the keyboard (see SHORTCUTS). To give the element a specific value, double click on the value given to change it or double click on the element, click on “VALUE” in the large lower window, click the “Save Attr”, then click “OK” or “Return” on the keyboard.

Setting up for DC and Transient Analysis

You will need to set up certain criteria for your DC and Transient responses for PROBE. To do this, go to the “Analysis” on the tool bar and choose “Setup” . Enable the DC and/or the Transient square windows and make sure to leave the other squares blank. Click on “DC Sweep” and/or “Transient” to enter the desired parameters (refer to the specific parameters from the relevant lab), then click on “OK”, and then “Close”. You are now ready for the next step before simulating and that is to SAVE YOUR SCHEMATIC FIRST! You can go to “File” and choose “Save” or you can use Ctrl+S on the keyboard (see SHORTCUTS). Once saved, then you can simulate; go to “Analysis” and then choose “Simulate”. You can also use the F11 key (see SHORTCUTS).

Changing Model Parameters

When using Schematic Capture, sometimes it is necessary to change specific parameters of an element, i.e., a different beta factor (bF) for a transistor may be desired. To do this, go to “Edit”, choose “Model”, then choose “Edit Instance Model”. After making the desired changes, it is good policy to delete parameters that you have NOT changed. For example, if the required parameters for alteration for a transistor were IS, VA, BF, CJC and RB, change these values and delete the remaining values like TF, TR CCS, etc. Remember to SAVE before you SIMULATE!

Alternatives to constructing additional circuits after constructing one

After completion of the first circuit, an alternative to construction additional circuits from scratch is to “Save As” another circuit and give it a different name. You can also copy it to a “New” file in the “File” menu. The odds are that you will be simulating circuits that will be mostly similar in configuration and it would be highly time consuming to construct each one individually when you only need to alter a few elements or parameters.

ERROR AND WARNING MESSAGES

Errors

If you get a Microsim Message screen that reads *ERROR, then guess what you have to do? Read the error message and then fix it! “X” out the screen from the upper right corner and go back to the Netlist Editor (go to “Analysis” , then choose “Examine Netlist”). Don’t forget to SAVE after editing before you simulate again!

Warnings

If you get a message screen that reads *WARNING but not *ERROR.. DON’T PANIC! The PROBE option should pop up shortly after (unless you are using the floppy drive - this may take a while longer), then you will be ready to plot. This is analogous to when you compile a high level program (such as C++) and, although you may get warnings, the program will still function.. and at this level that is all that matters for now.

NAVIGATING PROBE

Now that you are in PROBE, you can may get a message titled “Analysis Type” offering the option of “DC” or “Transient”. Choose whichever you need, it doesn’t matter which one you do first if you would like to analyze both plot types. To get the dependent variable, go to “Trace” in the top tool bar and choose “Add”. From the left column, you can choose a variable or a combination of variables. For example, if you want both your input and output voltage in a transient plot to be superimposed, just click on the first variable, hit the comma key (“,”) on the keyboard, then the second variable, then “OK” (or the “Return” or “Enter” key on the keyboard).

Some Quick Tips

If you are doing a Transient plot (or a DC plot) and you wish to get a DC plot (or a Transient plot) instead of doing another simulation (yuch!), just go to “Plot” on the upper tool bar, then choose “DC” (or “Transient”). Here’s some more navigating tips for your plots:

• To get more than one plot on a page:

Go to “Plot”, choose “Add Plot”, click on plot to select

• For writing the title to a plot (or excluding it):

Go to “Edit”, choose “Modify Title”

• To label or set the range of the Y or X axis:

Go to “Plot”, choose either “X” or “Y settings”

• To add text or arrows, etc., to plot:

Go to “Tools”, choose “Label”

• For Print Settings, etc.:

Go to “File” and.. you can take it from there. Hint: to get rid of those ugly headers and footers (Date, Temperature, etc.), choose “Page Set up”

SHORTCUTS

• To save after each editing: Ctrl+S

• To simulate (after saving each editing): F11

• To rotate an element, i.e., a resistor: Ctrl+R

• To get a new part from the “Draw” menu: Ctrl+G

• To copy an element instead of pulling from menu: Ctrl+C

• ..To paste element into place: Ctrl+V

• To Draw connecting wires: Ctrl+W

• To discontinue using element: Esc

REFERENCES OF PARAMETERS

Pulse input: PULSE( DC AC TD TR TF PW PER )

Piecewise Linear input: PWL( DC AC T1 V1 T2 V2… TN VN )

Decaying Sinusoidal input: SIN( DC AC FREQ TD DF THETA )

Where

DC = dc offset voltage

AC = alternating current amplitude

TD = time delay

TR = rise time

TF = fall time

PW = pulse width ( or “duty cycle”)

PER = period

FREQ = frequency in Hertz

DF = dampening factor in sec-1

THETA = phase angle in degrees

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