Project4s15 supplement

Supplementary Material

Cadence 6 Software Tutorials, continued

Overview

This supplement goes over details on:

Creating a schematic from scratch using the ami05_c6_customlib library
Setting up S-parameter tests from scratch using ADEXL software
Creating a symbol for a schematic/design
Using components from the library supplied in class, ami05_c6_customlib library

Part 1

In this part, simulations are performed on a simple 2-resistor voltage divider circuit using Cadence software and our ami05_c6_customlib library.

From a Linux terminal, Cadence6/Virtuoso should be available in the menu (Mosaic->Engineering->Electrical->Cdence->Cadence6)

From a PC terminal, you must first open a remote Linux session, (Start->AllPrograms->Mosaic->LinuxConnect->ToAnyServer), then proceed as for a Linux terminal

Create a new library "rfProj3" using MenuBar::File::New::Library from the Library Manager menu bar, and use the input parameters as shown below to create a 0.5 micron design

Make sure that you attach the proper tech library (ami 0.6u c5n) as shown below

Note: sometimes the software hides the popup window behind the windows

As shown below, highlight your new library on the left pane of library manager window, and create a new cell named "resDive_cell" using the MenuBar::File::New::CellView from library manager menu bar.

This circuit will be a simple 2-resistor voltage divider

Always name your circuit cells with the suffix "_cell" to indicate they are some smaller subcircuit of a larger circuit

Make sure that the "open with" option is "Schematics XL" (red arrow below)

NOTE: a common bug in Cadence is that the "new file" popup window is hidden behind your other windows

Next, add a pair of 50 ohm resistors from our ami05_c6_customlib library to the schematic using the "create instance" toolbar button at the red arrow below

Make sure you select the ami05_c6_customlib library (blue arrow below)

Make sure you select the R50 device (green arrows below)

You can rearrange locations of things on your schematic by using the "default selection" toolbar item (red arrow below)

Add the pins pin_in, pin_out, and pin_gnd using the "create pin" toolbar buton at the red arrow below

Make sure all pins are inputOutput as shown below (green arrows)

Wire the circuit using the wiring toolbar item shown at the blue arrow below, and the final circuit should appear as follows

Check and save your schematic using the "check and save" toolbar item at the yellow arrow above.

If any errors are found, a popup should appear.

Print the schematic of your "resDiv_cell" as above and turn it in. ( P6 )

Select one of your resistors, and type "q" on your keyboard, and you should see the object properties popup as below, where you can inspect/edit properties of a device

Next, create a symbol for your circuit using MenuBar::Create::Cellview::FromCellview as illustrated below

In the popup shown below, make sure the toviewname is symbol, fromviewname is schematic, and the type is schematicSymbol

In the pop-up, set the pin locations as follows (red arrows below)

The symbol should be created as shown below (green arrow below)

Check and save the symbol (red arrow above)

Close all of your schematic and symbol windows

Ceate a new schematic, as before.

Name this schematic "resDiv_cell_sparam"

Note: always name testbenches with a prefix the same as the name of the cell being tested and with a suffix indicating the test being done

This new circuit/cell will be the testbench (containing the external test circuits) for doing s-parameter testing of the "resDiv_cell" cell. Create the new testbench using the MenuBar::File::New::CellView from library manager menu bar, as shown below.

Make sure that the "open with" option is "Schematics XL"

Next, add an instance of our new "resDiv_cell" from our rfProj3 library to the schematic by using the "create instance" toolbar button at the red arrow below

Make sure you select the rfProj3 library (blue arrow below)

Make sure you select the resDiv_cell device (green arrows below)

You should see your symbol appear in the schematic as shown above, after you click in the schematic

(Sometimes if your cell has a odd center defined, the symbol may be placed off-screen out of sight)

Next, add an instance of a ground symbol to your schematic by using the create-instance toolbar button again The ground comes from the analogLib sources/global library, as shown below

Next, add an instance of a "psin" port to your schematic using the create-instance toolbar button again.

The psin port comes from the analogLib sources/ports library, as shown below

Wire the schematic as shown above.

Check and save your schematic using the "check and save" toolbar button at the yellow arrow above.

If any errors are found, a pop-up should appear.

Save the schematic of your cell as above and turn it in. ( P7 )

Finally, create the simulation setup

Run ADE-XL from the MenuBar::Launch::ADEXL command in the schematic editor of the new testbench as shown below

Make sure to use the "create new view" option on the popup (blue arrow below)

The ADE-XL window should then appear as shown below

Click on the schematic tab (blue arrow above)

The testbed schematic should become visible as below

Then select MenuBar::ADEXL::Create::Test, as below:

The Test Edior window should appear (red arrow below), along with the testbench being chosen:

Choose the cell of your testbench (blue arrow above), as in the popup above, and click OK

The ADE-XL test editor should appear, as shown at the red arrow above, behind the popup.

Note for future reference: If we used a variable in our testbench, we would next need to run MenuBar::Variables::CopyFromCellView to load them into the window, and enter values for them in the window. We do not have to do that here, since we have no variables defined in our testbench schematic.

Click on the MenuBar::Analysis::Choose (purple arrow below)

Set up the s-parameter analysis as follows:

Click the "sp" button for s-parameter analysis (red arrow below)

Then, click the select button (blue arrow below) to enable you to select your two "psin" sources from the schematic

After selecting, you should see ports "/PORT0 /PORT1" (green arrow below).

Note for future reference: if this was a transient analysis instead of s-parameters, you would select the output ports using the MenuBar::Ouptputs::ToBePlotted::SelectOnSchematic

Note: a bit of an oddity is that when plotting s-parameers S11 is for /PORT0 and S22 is for /PORT1

Finally, set your sweep from 0.01 GHz to 0.1 GHZ (yellow arrow below)

After clicking OK, the test editor should appear as below

Note that your new "sp" analysis should now appear in the analyses pane

Return to your ADE-XL window, and in the left pane, expand the "Tests" item to verify that the "sp" s-parameter analysis is present (blue arrows below)

Then, click the green "run simulation" toolbar button (red arrow below)

If the simulation runs properly, you should see "finished" in the lower left corner area (green arrow below)

Return to the ADE-XL tab as below (blue arrow below)

Then, click the ResultsBrowser button (red arrow below) to see the plotting window for s-parameters.

The Visualization and Analysis XL tool should appear as below

Select the "dB20" processing (red arrow below)

Select the "sp-sp" data (red arrow below)

Select S11 and S21 (green arrows below)

Right click over S11 and select the "Plot Signal" option (yellow arrow below)

When the plot appears, the background will be black. Right-click to set a white background as below.

Right-click the traces to set the colors different as above, and with S11 as a solid line "thick," and S21 as a dashed line "thick."

You should see the S-parameters plotted as above.

Save the plot of your s-parameters similar to above and turn it in. ( P8 )

Hint: it is easy to check if your answers are correct by using ADS to run the same simulation.

Change the "Default" near the red arrow above to "impedance" as shown below (blue arrow below)

As before, right-click S11 (red arrow below) and choose the "new window" plot option in the popup menu

Right-click::View::FitSmith in the Smith chart plotting area to fit it as below

Save the plot of your Smith chart as above and turn it in. ( P9 )

Finally, make sure to save all of your test settings from within ADE-XL.

Use MenuBar::Session::SaveState from within TestEditor as shown below

Make sure to save the state in the CellView (red arrow below)

Note: If you closed Test Editor and the window is not open, you can reopen it by right-clicking the test item under "Tests" in "Data view" pane on the left side of the ADEXL window

Note: from within ADEXL there is a second type of saving an overall ADEXL state from the ADEXL MenuBar as MenuBar::File::SaveSetupState It does not appear that this second type of saved state saves the test setup of the test editor pane

You should be able to see your saved test state from within Library Manager as follows, with the saved test setup "spectre_state1" at the red arrow below

Save the image of your Library Manager showing your saved test setup as above and turn it in. ( P10 )

Copyright © 2010-2015 T. Weldon
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