cadence and agilent ads rfic tutorial

5/22/13 Cadence and Agilent ADS RFIC Tutorial

thomasweldon.com/tpw/courses/radio/hpads/cadence2010.html 1/30

Cadence and Agilent ADS RFIC Design Tutorial

T.P. WeldonCopyright 2010

Overview

This is a simple tutorial for using Agilent ADS, Cadence, and our custom libraries to design RFIC's. The libraries will greatly simplify your effort.

In the following, you will be supplied with a Cadence library of IC layout components along with a companion schematic/simulation library for Agilent ADS. Using thesetwo libraries will save you many hours of time. If you design a circuit using these library components, you will be able to place all of your integrated circuit components

in 5 minutes, automatically. After component placement, you will only need to wire the components together.

Preliminary tips and notes:

Save yourself from wasting many hours: Use our custom Cadence library along with the companions Agilent ADS library

Use subcircuits wherever you intend to repeatedly use a circuit. In this way, you will only have to do the layout once.If you plan to use an inductor, read section 8 below for workarounds.

In naming your files, avoid the use of hyphens, use undercscores instead.There should be only one ground in the entire design, at the top level connected to pin 30 of the padframe. There should be no ground in any subcircuit, use a

pin with a name such as "mysubcktgnd" in any subcircuit.Do not name any subcircuit pins "vdd" or "gnd", since these are reserved system names/keywords. Instead, give your subcircuit pins names such as

"abcAmpGnd" and "abcAmpVdd."

All pins should be "InputOutput" type. Avoid using "Input" or "Output" type pins.You must copy the BSIM3 models into your test/simmulation schematics from the tpw-IFamp-sub-transTest schematic provided in the ADS library.

Use the standard component values in the libraries. For example, you need a 250 ohm resistor and it is not in the library, use two 500 ohm resistors inparallel. Only in extreme circumstances should you consider using custom components. Ask the instructor before you use any custom components.<>

Do not forget to add the "ptap" substrate contacts at your pin30 ground pin. These are needed to ground the substrate of your integrated circuit.

1. Download and install the Agilent ADS library

Use this Agilent ADS library for entering schematics for all circuits that will be fabricated on your integrated circuits. In your schematics, only use the components included in the following library.

To minimize problems and confusion with prior projects,you may want to move all old ADS projects and folders to a folder named "old."

Download the Agilent ADS Library tpw_ami05_Fall2010_prj_ads.zipExtract this in your ADS directoryRename the tpw_ami05_Fall2010_prj directory with your initials "xyz" replacing the "tpw" above.

You MUST rename it to prevent problems when your chip is sent for fabricationRun ADS, and open the project, it should resemble the following

http://thomasweldon.com/tpw/courses/radio/hpads/tpw_ami05_Fall2010_prj_ads.zip



You should construct your circuit design only using the components included in the library, such as C1pf, R10k, R1k shown above.To use these components in a schematic, MenuBar::Insert::Component::ComponentLibrary as illustrated below

Open the tpw-top-example schematic, it should contain the following

The large 40-pin subcircuit is for the padframe, and you should use this in your top-level schematic for layout of your integrated circuit. It will result inautomatic layout of your padframe along with correctly numbered pins and ESD protection (static protection on all pins). As a rule, always ground pin 30 as shown in the example above. Pin 30 has the shortest wirebonds. Connect your circuits to the padframe as shown above. However, your final design should not have transistors connecting to the padframe as shownabove, rather, you should have subcircuits connecting to the padframe.

Descend through the padframe hierarchy to see the ESD protection transistors. Select the padframe and push the button Return to the schematic and note that the transistor in the schematic is actually one of the components from the library, wn50, a 50umx0.6um NMOStransistor.For an example of a subcircuit using the library components, open the tpw-IFamp-sub schematic as shown below



If you zoom into the top left components, note that they a C4pF capacitor and wp100 pmos FET. Both are from the component library as shown below. Since they are subcircuits, they are numbered X19 and X2. You can descend into the subcircuit and see the circuit and device parameters, just as anyother subcircuit. Be careful not to change any parameters of devices in the library!

View the tpw-IFamp-sub subcircuit symbol using MenuBar::View::CreateEditASchematicSymbol and observe the symbol below.

Use MenuBar::View::CreateEditASchematicSymbol to return to the schematicUse similar naming conventions with your initials for your circuits, so the instructor will be able to navigate through the final project that yousubmit. This also helps prevent problems when all of the integrated circuits for our course are submitted for fabrication.To properly test your subcircuits, create a separate schematic with the subcircuit symbol connected to the test equipmet as illustrated in the transient testcircuit tpw-IFamp-sub-transTest transient test circuit illustrated below:

Press the simulation button to observe the transient output below:



Use MenuBar::Simulate::AnnotateDCsolution to observe bias levels as below

Push into the subcircuit hierarchy and annotate the dc solution of the subcircuit.Note the s-parameter test circuit and the intermodulation test circuit that are also provided.

Use similar naming conventions with your initials for your circuits, so the instructor will be able to navigate through the final project that you

submit. This also helps prevent problems when all of the integrated circuits for our course are submitted for fabrication.

2. Download and install the Cadence library

Use this Cadence library for entering layouts for all circuits that will be fabricated on your integrated circuits. Each component in the Cadence

library corresponds to a component in the ADS library, and will be automatically created without you needing to enter every component layout by

hand.In your layouts, only use the components included in the following library.

!!! STRONGLY RECOMMENDED: !!!

To minimize problems and confusion with prior projects,you may want to move all old Cadence projects, libraries, and folders to a folder named "cadence/NCSU/old"

and open Cadence and run MenuBar::File::DeleteLibrary to remove the old libraries from the LibraryManager list.

Download the Cadence AMI06 Library tpw_ami05_Fall2010_prj_cadence.zipSee above recommendation to remove all old libraries from Cadence before you do anything!

Extract this in your cadence/NCSU directoryDo not rename the directory yet, it must be renamed from within Cadence

Add the following line to the end of your cadence/NCSU/cds.lib file: DEFINE tpw_ami05_Fall2010_prj /afs/uncc.edu/usr/WHATEVER/linux/cadence/NCSU/tpw_ami05_Fall2010_prj

where WHATEVER is your home directory path

Run CadenceFrom within Cadence, select the tpw_ami05_Fall2010_prj library and then MenuBar:: Edit::Rename to rename the directory the same as above with your

initials "xyz" replacing the "tpw" (Cadence and ADS directory names MUST be identical and end with _prj). Rename as below:

http://thomasweldon.com/tpw/courses/radio/hpads/tpw_ami05_Fall2010_prj_cadence.zip



Look in the new library. It should resemble the following:

Open the schematic of example file tpw-top-example in Cadence by clicking/highlighting on the tpw-top-example in the cell column (as above), and

double-clicking the schematic in the view column (to the right of the cell column). The schematic below should appear (corresponding to the ADS

schematic of the previous section).

Open the layout of the example file tpw-top-example in Cadence by clicking/highlighting on the tpw-top-example in the cell column (as above), anddouble-clicking the layout in the view column (to the right of the cell column).



Use MenuBar::Options::Display to see all layers and pins as below:

The example chip should open as below ( )

The ground pin is near the bottom center

Do not forget to add a ground pin to your circuit and connect it to the substrate using metal1 and ptap instanceas illistrated by zooming in to pin 30 as

shown below.



For future reference, the ptap instances are created using MenuBar::Create::Instance popup::library::Browse NCSU_TechLib_Ami06 cell ptap as

illustrated below

At the upper right of the layout, near pin 1, note the layout of the transistor and its connection to the pins as illustrated below:

For future reference, the wiring was done by first selecting metal1 or metal2 in the LSW palette window, then using MenuBat::Create::Path as below:



Also, note that you can turn on "nets" to see where each device should be connected to other devices based on the schematic. To see these nets, use

MenuBar::Options::Display::Nets. (This example may not show nets, due to the way it was created.)

Run DRC on the layout using MenuBar::Verify::DRC, and observe that the icfb window shows no errors after it runs, as below

Run extraction to prepare for LVS (layout versus schematic) using MenuBar::Verify::Extract. as below.Set the LVS options as below using the MenuBar::NCSU::LVSoptions



Make sure there are no errors as indicated in the icfb window below (see arrow below)

Next run LVS (layout versus schematic) using MenuBar::Verify::LVS as below. If a Forms Contents Different window pops up, select "use form contents"

and use the two browse buttons below to select the schematic view and extracted views of the tpw-top-example cell. After browsing, the form contents

should be as below. Then click on the RUN button, and look for the succeed message popup below.

WARNING: succeed does NOT mean that your layout passed LVS, it only means LVS ran completely without crashing.



Finally, you must check the LVS output to see if your layout matches the schematic. Click the LVS button, and read the output to check for errors or

warnings. A successful LVS MUST have the net-lists match message as below.

IT IS MANDATORY that all of your designs pass LVS at the top level including the padframe. NO EXCEPTIONS!

It would be good idea to create a zip-archive of your Cadence project directory and your Agilent ADS project directorySee Section 6 below if you get LVS errors where "netlists match logically but with mismatched parameters."

As a rule, consider saving backups of work frequently, so you can return to a "known good" state.

Other useful tips

To remove or resize a bounding box: First, in the LSW window, LSW::Edit::SetValidLayers and add prBound dg by checking the box as shown below

After doing the above, you will be able to select the box and delete it from the layout if desired



If you have residual/remaining error/warning boxes use MenuBar::Verify::Markers::DeleteAll, and run any necessary checks again

3. Example schematic and simulation using the library

The schematic created in this section will later be exported for layout in Cadence.In your schematics, only use components from the Agilent ADS library that was installed in Section 1 above.

Creating your ADS Schematics

Run Agilent ADS and open your "xyz"_ami05_Fall2010_prj project

Create a new schematic "xyz"-amp-sub using MenuBar::File::NewDesign as below; (click "no help needed" in the popup)

Enter the following schematic (carefully note the devices from the library, the names of the ports, and the absence of blue dots at certain wire crossovers) The annotated voltages will appear later, after simulation.

There should be only one ground in the entire design, at the top level connected to pin 30 of the padframe. There should be no ground in any subcircuit,

use a pin with a name such as "mysubcktgnd" in any subcircuit.

Do not connect all of your circuits to a single vdd pin, since one bad/oscillating circuit would then cause your whole chip to fail. For exmple, if your projectwas to create a negative indcutor and a negative capacitor, have a separate vdd pin for each circuit so you could disable one of them if it fails.

Do not name any subcircuit pins "vdd" or "gnd", since these are reserved system names/keywords. Instead, give your subcircuit pins names such as

"abcAmpGnd" and "abcAmpVdd."

All pins should be "InputOutput" type. Avoid using "Input" or "Output" type pins.

Do not use pin names such as "vdd" or "gnd" to avoid problems with global variable names



To use these components in a schematic, MenuBar::Insert::Component::ComponentLibrary and right-click the component as illustrated below

Create a symbol for the schematic using MenuBar::View::Create/EditSymbol as below. (If you wish, you can rearrange pin locations from the defaults)



Save all of your work.

Next, create a transient test circuit "xyz"-amp-sub-transtest using MenuBar::File::NewDesign

Place your new subcircuit in the schematic using MenuBar::Insert::Component::ComponentLibrary and right-click the component

Place a ground pin using the button on the menu bar and wire it to Pampgnd pin (use the button to wire).

Add a 5V dc source as below:

Add an ac VtSine source at 10 MHz an 0.1 V as on the left button below

Place a 2 nH in series with 5 pF load representing the output loading of the IC package and PC board as below

Add wire labels vin and vout using MenuBar::Edit::WirePinLabel as follows

Add Simulation dc and transient simulation as below

Finally, add the BSIM 3 models to your schematic by copying and pasting them from the tpw-IFamp-sub-transTest schematic provided in the ADSlibrary. The final schematic should be as follows:



Simulate the design using the simulate button and make sure the popup windows do not show errors.

Use MenuBar::Simulate::AnnotateDCsolution to check that your bias levels are correct. Push into the hierarchy of the symbol using the button, andcheck the bias levels in the subcircuit match the bias levels in the subcircuit schematic given above. Click the rectangular plot button in the popup, and add a plot of vin and vout as follows:

Fix any errors, so that your circuit is working properly.Save all of your work.

Next, create another new schematic "xyz"-amp-top that will be the top-level of your integrated circuit, including your padframe

Only use the word "top" in the name of only one schematic, to indicate the top-level of your design!Add the padframe compnent and your xyz-amp-sub as below. Connect your amp to pins 31-34 of your padframe as below. Add a ground to pin 30 as

below. As shown below, share the ground pin with ground and Pampgnd pin of your subcircuit, to save pins.



It would be good idea to create a zip-archive of your ADSproject directoryAs a rule, consider saving backups of work frequently, so you can return to a "known good" state.

4. Exporting your ADS schematic to IFF format for layout

The schematic created in Section 3 will be exported for layout in Cadence.Make sure that your ADS project directory "xyz"_ami05_Fall2010_prj and Cadence directoriy have the same name before proceeding.

Open your top-level schematic with the padframe, "xyz"-amp-top

Export an IFF file using MenuBar::File::Export with approriate options set as illustrated below. The default library name should be the name of your project directory, such as "xyz"_ami05_Fall2010_prj

This will create a file in your ADS directory called tpw-amp-top.iff.

5. Importing your ADS schematic IFF file to Cadence for layout

The IFF file created in Section 4 will be imported for layout in Cadence.Make sure that your ADS project directory "xyz"_ami05_Fall2010_prj and Cadence directory have the same name before proceeding.



Copy the IFF file tpw-amp-top.iff to your cadence/NCSU directoryRun Cadence

Make sure that you have first installed and renamed the Cadence library "xyz"_ami05_Fall2010_prj as described above in the installation of the Cadencelibrary

To import the design: In the Cadence icfb window, run MenuBar::IFF::ImportIFF as below: If you are overwriting an existing design, the safest way is to delete it within Cadence before importing, since the "do not overwrite" option is selectedbelow.

Refresh the file view MenuBar::View::Refresh in the Cadence Library manager window. Accept any "RefreshCDFs" popup.

You should now see your new schematics in the library: xyz-amp-sub and xyz-amp-top as below

Save all of your workClose Cadence

It would be good idea to create a zip-archive of your Cadence project directory and your Agilent ADS project directoryAs a rule, consider saving backups of work frequently, so you can return to a "known good" state.If you accidentally corrupt the library, just re-extract the library and overwrite your corrupted files. (You may have to rename the library

back to "tpw" before extraction)

6. Schematic-driven layout in Cadence

The IFF file created in Section 4 will be imported for layout in Cadence.Make sure that your ADS project directory "xyz"_ami05_Fall2010_prj and Cadence directory have the same name before proceeding.

Run Cadence

In Library Manager, open the "xyz"-amp-sub schematic as below

The schematic should be the same as your ADS schematic:



In the Virtuoso schematic window, use MenuBar::Check::CurrentCellView and observe the icfb window to ensure there are no errors.

From library manager, you can also open the symbol to check that it is the same as in ADS:

Next, return to the schematic in Virtuoso to begin schematic-driven layoutFrom the schematic Menubar::Tools::DesignSynthesis::LayoutXL as below. Click OK on the "create new" popup.

And create new cell at the next popup as follows. Choose the Tool=Virtuoso as shown below

The Virtuoso layout window will appearTurn on Virtouso features with MenuBar::Tools::LayoutXL to enable schematic-layout connectivity features

Then from the Layout window use the command MenuBar::Design::GenFromSource as shown below. In the popup window below, make sure to:

Set IO pins to metal1 geometricClick the APPLY button so all the pins listed in the box switch from pwel to metal1



Set pin label to text display (option height = 1 or 2)

click OK

Bounding box layer is not included in the normal palette, whic makes them unadjustable. Tofix this issue, in the LSW window use the menu bar commandLSWmenuBar::Edit::SetValidLayers and add "prBound dg" by checking the box as shown below

After doing the above, you will be able to select the box and change/delete it from the layout if desiredNext, automatically place the devices in the Virtuoso layout menu using MenuBar::Edit::PlaceAsInSchematic and the devices will automatically be placed.

Placement will not be perfect.Press the f-key on your keyboard to rescale the layout to fill your screenRearrange the devices roughly in the bounding box area as below. (Select the whole area to see the tiny invisible parts)

Shrink the bounding box at this point, if you wishUse MenuBar::Connectivity::ShowIncompleteNets and choose SelectAll to see the connections that you must make, as below



Note that when you select any device in the layout, the corresponding device is highlighted in the schematic and vice-versa.You can hide the flight lines with MenuBar::Connectivity::HideIncompleteNetsNext, set MenuBar::Options::Display to check pinNames and layers 1-32 as below

Then choose metal1 or metal2 in the LSW palette and begin connecting pins using MenuBar::Create::Path

Run MenuBar::Verify::DRC frequently as you wire the circuit, to catch errors as you workAs you make connections the flight-lines should disappear. (The layout editor is a bit particular, and will require your path to cross over the pin before the



flight line disappears ... even when a connection is made to neighboring metal)Use MenuBar::Create::Contact to create vias between metal layers (M2_M1) and contacts to the substrate (M1_P or ptap).

Do NOT wait until the end to do DRC!!Your final layout may look like:

Final checks of your subcircuit layout

Run DRC with no errors: MenuBar::Verify::DRC (see DRC examples above)Run Extraction with no errors: MenuBar::Verify::Extract (see extraction examples above)

Run LVS with no errors: MenuBar::Verify::LVS (see LVS examples above)The LVS output file must say "the netlists match"See below if you get LVS errors where "netlists match logically but with mismatched parameters."

Next, layout the top cell with the padframe,Open xyz-amp-top schematic in Cadence Library Manager

The schematic should be as follows:

Run a check MenuBar::Check::CurrentCellView There are 34 warnings (yellow highlights above). MenuBar::Check::FindMarker to see the warnings are for floating pins

Next, return to the schematic in Virtuoso to begin schematic-driven layout

From the schematic Menubar::Tools::DesignSynthesis::LayoutXL as below. Click OK on the "create new" popup.

Next, begin schematic-driven layou as before for the subcircuittFrom the schematic Menubar::Tools::DesignSynthesis::LayoutXL as below. Click OK on the "create new" popup.

As before, create new cell at the next popup as follows. Choose the Tool=Virtuoso



The Virtuoso layout window will appear

Turn on Virtouso features with MenuBar::Tools::LayoutXL to enable schematic-layout connectivity featuresThen from the Layout window use the command MenuBar::Design::GenFromSource as shown below.

In the popup window below, make sure to:Set IO pins to metal1 geometricClick the APPLY button so all the pins listed in the box switch from pwel to metal1

Set pin label to text display (option height = 1 or 2)set boundary width 1500

click OK

Bounding box layer is not included in the normal palette, whic makes them unadjustable. Tofix this issue, in the LSW window use the menu bar commandLSWmenuBar::Edit::SetValidLayers and add "prBound dg" by checking the box as shown below

After doing the above, you will be able to select the box and change/delete it from the layout if desiredPress the f-key on your keyboard to rescale the layout to fill your screenRearrange the devices roughly in the bounding box area. (Select the whole area to see the tiny invisible parts)

Place the "gnd" pin near pin 30 and place the amp subcircuit near pins 31-34 as below.

Use MenuBar::Connectivity::ShowIncompleteNets and choose SelectAll to see the connections that you must make, as below

Note that when you select any device in the layout, the corresponding device is highlighted in the schematic and vice-versa.

You can hide the flight lines with MenuBar::Connectivity::HideIncompleteNetsNext, set MenuBar::Options::Display to check pinNames and layers 1-32 as below

Then choose metal1 or metal2 in the LSW palette and begin connecting pins using MenuBar::Create::Path or MenuBar::Create::Rectngle

At the ground pin of pin 30, add 10 contacts to the substrate below a large metal1 rectangle as shown below



Connect all the remaining pins until your final layout is completed as illustrated below:

Final checks of your integrated circuit layout

Run DRC with no errors: MenuBar::Verify::DRC (see DRC examples above)Run Extraction with no errors: MenuBar::Verify::Extract (see extraction examples above)Run LVS with no errors: MenuBar::Verify::LVS (see LVS examples above)

The LVS output file must say "the netlists match"If you get LVS errors where "netlists match logically but with mismatched parameters," then you most likely used incorrect settings when you used

the Cadence iff-import to import schematics, and you probably accidentally overwrote some Cadence library files. Typically, this type of error willmention some 5 um device was 0.6 um.

To fix this LVS "mismatched parameter" error use following steps

make a backip zip of your cadence directory before doing anything! then, download my original Cadence library, and install it without changing the name to your initials. run cadence, and from within library manager, copy my entire library into your library and overwrite everything. the only things it will

overwrite are the original library files that you should not have changed anyway. If you get a pop-up window with "fix-errors" and"overwrite" buttons at the bottom, first click "fix-errors," then click "overwrite," then OK.

Re-run LVS and the mismatch errors should not occur

IT IS MANDATORY that all of your designs pass LVS at the top level including the padframe. NO EXCEPTIONS!

It would be good idea to create a zip-archive of your Cadence project directory and your Agilent ADS project directoryAs a rule, consider saving backups of work frequently, so you can return to a "known good" state.

7. Exporting your design in cif format for MOSIS fabrication

Run CadenceFrom the icfb window MenuBar::File::Export::Cif as below



Recheck the cif file by importing it and viewing it using icfb MenuBar::File::Import:Cif as follows

Edit the new library to attach the ami06 tech library using MenuBar::Edit""AttachTechLibrary (because the full path to NCSU libs above is a problem) Perhaps copying the techlib to your directory would workaround this

Note: there may be import errors/problems if the top layout cell has the same name as the cif file. In this case, try renaming the cif file before import.

The resulting layout should show the basic structure, even if the layers are mislabeled as follows



Another vendors cif-viewer would be a better check

Finally, see the mosis website for the latest submission details

8. Inductors

Inductors do not seem to be supported well in the NCSU kit, so some workarounds are necessary.

A 3.5 nH inductor schematic and corresponding layout are provided.Only use the 3.5 nH inductor in your Agilent ADS library. For accurate simulation, add a series resistor equal to the resistance of the metal computed from the

MOSIS ohms per square for each metal. Metal3 and metal2 are in parallel.

Export the inductor to Cadence in your schematic. It might not lay out automatically in Cadence, since it has no pins/ports. It was not possible to place pins on

the inductor, because Cadence sees the two pins as short-ciruited in the inductor.Two workarounds are needed:

After export to cadence, and after placing the devices in layout, delete the inductor from the Cadence schematic, replacing it with a short circuit.

Very carefully place and connect the inductor in the layour. Take great care with this, since LVS will not catch any errors with short-circuited inductors..

9. Other workarounds and tips

If your help menus are not working, try directly accessing the help tree through a browser

<>Help doc root: file:///opt/coe/cds2008/ic5/ic5/doc/ on linux or file:///N:\.root\uncc.edu\coe\linux\opt64\cds2008\ic5\ic5\doc on windoz

a

10. Other helpful websites

http://www.eda.ncsu.edu/wiki/NCSU_EDA_Wikihttp://www.eda.ncsu.edu/wiki/NCSU_CDK

http://www.eda.ncsu.edu/wiki/NCSU_CDK_download

http://www.ece.umd.edu/~dilli/research/layout/cadencetutorial/cadencedemo9.htmlhttp://www.cadence.com/support/university/ww_usp.aspx

http://www.ece.nmsu.edu/vlsi/cadence/CADENCE%20Manual.pdf

STOP HERE

STOP HERE

The following methods are not required for our class,

they are used in full-custorm layout instead of using our library components.

http://www.mosis.com/

http://www.eda.ncsu.edu/wiki/NCSU_EDA_Wiki

http://www.eda.ncsu.edu/wiki/NCSU_CDK

http://www.eda.ncsu.edu/wiki/NCSU_CDK_download

http://www.ece.umd.edu/~dilli/research/layout/cadencetutorial/cadencedemo9.html

http://www.cadence.com/support/university/ww_usp.aspx

http://www.ece.nmsu.edu/vlsi/cadence/CADENCE%20Manual.pdf



Exporting ADS Schematics to Cadence

DO NOT DO THESE STEPS, IF YOU ALREADY LOADED cadence_ami06partlibFALL07 IN A PREVIOUS LAB

Download the Cadence library cadence_ami06partlibFALL07.zip in N:/uncc/usr/r/tpweldon/pub/pubReadable (you must access this file from a campuscomputer)

Move the file to your NCSU directory where "junk1" is and extract the file

Close CadenceFix the links in ~/cadence/NCSU/cds.lib by opening cds.lib (use the nedit/gedit editor in linux)and editing it to add the lines

DEFINE ami06partlibFALL07 /afs/uncc.edu/usr/WHATEVER/linux/cadence/NCSU/ami06partlibFALL07

where WHATEVER is the path for your own directory (see the junk1 path in the cds.lib file, or type pwd in a terminal)Re-open/run Cadence

The new library should appear as below

Download the ADS file cadenceExample1_prj.zip in N:/uncc/usr/r/tpweldon/pub/pubReadable (you must access this file from a campus computer

Extract the file in your ADS directory This ADS example shows you how to export an ADS schematic to Cadence.

Frst, make sure everything is installed properly by opening the IFamp-sub2-transTest schematic, and run the transient test to see the result below:

Open the schematic IFamp-sub2-export-iff which only contains the symbol for the circuit as below:

To export the schematic to cadence in iff format, click MenuBar::File::Export in ADS, and export as type iff, as below



Click the MoreOptions button, and check that the options show overwrite iff, and 3 of 4 checkboxes are checked, and default library name should beami06partlibFALL07, schematicHeriarchy includes currrent design, projects, and NO library parts (the library parts are already in ami06partlibFALL07). The

options should appear as below:

After exporting the iff file, it should be somewhere in your ADS directory tree, typically the same directory as the schematic. Copy this file to your

cadence/NCSU directory.

Before running cadence icfb to import the iff file, you must first have this line somewhere in your .cdsinit file:load("/afs/uncc.edu/coe/unix/opt/ads2006/links/tools/iff/cadence/composer/mdsinit.il")

Run Cadence, and you should see the IFF->importIff option in the icfb menu-bar (in the icfb text-window not the icfb file window). Click the IFF menu bar

button, select the iff file to be imported as below.

Check/activate the three "do not" buttons, and click OK to convert. In the pop-up, attach to existing techfile, attach to the proper library (ami06), as illustrated

in the three panes below:.



If all goes well, you should be see the new library cadenceExample1_prj in Cadence along with the library cell IFamp-sub2-export-iff as shown below.

In Cadence, open the schematic of your top-level Cell IFamp-sub2-export-iff as shown below

In Cadence, open the schematic of your next-level Cell IFamp-sub2 as shown below



After you open the schematic, check the cellview: MenuBar::Check::Cellview. Hopefully, no errors.

To check the warnings, MenuBar::Check::FindMarker and double-click any warnings in the pop-up

Also remove power supplies and any ADS-specifice items such as variables, harmonic balance boxes, transistor models, power supplies, etc.

Next create the layout cellview by selecting the low-level cell IFamp-sub2 in Cadence LibraryManager andMenuBar::File::New::CellView. And choose

Tool=Virtuoso as below:

For Full-Custom-Schematic-Driven-Layout (we will not do this)

From the schematic Menubar::Tools::DesignSynth::LayoutXLAnd create new cell

And choose the Tool=Virtuoso as shown below



To automatically create a Full-Custom-Schematic-Driven-Layout from the schematic, from the Layout window MenuBar::Design::GenFromSource andselect all the pins and metal1 and click update so the pwells below change to metal1 as shown in the options below

The devices should be laid out approximately as in the schematic as illustrated below.

Set MenuBar::Display options to DisplayLevels:1-32, view nets if desired , PinNamesif desired as below



Note that when you click any device in the layout, the corresponding device in the schematic is highlighted

d

ff

To remove or resize a bounding box: First, in the LSW window, LSW::Edit::SetValidLayers and add prBound dg by checking the box as shown below

Then you will be able to select the box and delete it from the layout if desired

If you have residual/remaining error/warning boxes use MenuBar::Verify::Markers::DeleteAll, and run any necessary checks again

Copyright © 2010 T. Weldon

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