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Things You Didn't Know About Virtuoso: The (Setup) State of Things

Comments(0)Filed under: Custom IC Design, Virtuoso, Virtuoso Analog Design Environment, analog, ADE, ADE-XL, ADE-GXL, IC 6.1.5, Virtuoso IC6.1.5, Analog Design Environment, Analog Design Environment, IC615, Variability Aware Design, setup states

Apologies for the long delay between articles (best intentions and all that).  I last left you with an article about how to parameterize and manipulate device properties in your design without having to edit the schematic.  A very handy feature.  So there you are -- creating and matching and ratioing parameters willy-nilly.  You've changed values and defined ranges and run sweeps. 

And now you're wondering--how in the world can I keep track of all this information?  How do I re-use a particularly good set of parameter values that I found during a sweep or optimization and run a Monte Carlo or Sensitivity Analysis on it or simulate it over corners?  And while we're on the subject, I need different simulation settings when I run Monte Carlo as opposed to sweeps and corners.  It's a pain to have to do all this hand-editing or reload old simulation history items to switch back and forth.  What if I make a mistake?

Don't worry.  There is a better way. 

Setup States

Setup states are analogous to ADE L states, only in this case they apply to the whole ADE XL environment -- multiple tests, specifications, sweeps, corners, parameters, setups for different run modes.  All or any part of the setup can be saved to a setup state and reloaded fully or partially when needed for a later task.

Saving

In general, setup states are managed from the Data View Assistant.  It's easy.  Just set up everything the way you want and click RMB (right mouse button)->Save Setup State over the Setup State section of the Data View Assistant.  A form will appear allowing you to name the setup state and select which elements of the ADE XL setup you want to be saved--Tests, Variables, Parameters, Run Mode, Run Options, Specifications, Corners, Model Groups and Extensions.

Loading 

To load a setup state, expand the Setup State section of the Data View Assistant and click RMB->Load on the one you want to load.  A similar form will appear allowing you to select which elements you want to load.  At the bottom of the form is a little pulldown which lets you specify how you want the setup to be updated.  I'll give a brief description, but the documentation walks you through a much better example.

  • retain--Leave existing items unchanged.  Append new items.
  • merge--Overwrite values of matching items.  Append new items.  Leave anything else alone.
  • overwrite--Overwrite values of matching items.  Append new items.  Delete everything else that doesn't exist in the setup state

Special Features for Variables and Parameters

Lastly, in IC 6.1.5 ISR12, there are some new features which make it easier to save and load setup states containing just the settings for variables and parameters. 

  • After running a sweep or an optimization or a sensitivity analysis, you can click the right mouse button on the grey "Parameters" line above a particular simulation result in the Results pane and select "Save variable and parameter values to Setup State." This will create a new Setup State containing only the variable and parameter values for that design point.  Then you can load these values and run further analyses such as Monte Carlo, High Yield Estimation, Worst Case Corners, Sensitivity Analysis or use those values as the starting point for an Optimization run. 

Did you read that?  You can do every analysis in ADE XL and GXL on any combination of device parameter and design variables values--without having to edit the schematic.  That really simplifies "what-if" experiments.

  • You can directly save and load Setup States from new fields at the top of the Variables and Parameters Assistant (Window->Assistants->Variables and Parameters).  Also, you can use the little icon there that looks kind of like 2 pieces of paper with a magnifying glass to bring up a table comparing the values of the variables and parameters in any existing Setup State to the values of the active setup.  This is a really easy graphical way to pick a point as a result of an optimization or sensitivity analysis and compare it with the existing schematic design or with any other point to see what device parameters changed.

Stacy Whiteman

 

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