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Welcome to AMS in ADE

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Welcome to the integration of the Virtuoso^® AMS simulator and the Virtuoso^® Analog Design Environment (ADE).

This document highlights the following

• Features of AMS in ADE
• For ADE Users: Differences to Expect When Using AMS in ADE
• For AMS Users: Differences to Expect When Using AMS in ADE
• Where to Get More Information

The integration of the AMS simulator and ADE creates a design environment with the look and feel expected by analog and mixed-signal designers who already use ADE. When using this integration, you can access designs using the same tools you currently use for pure analog and mixed signal designs.

Features of AMS in ADE

The integration of the AMS simulator and ADE has the following features:

• State files from other simulators
  When you use the AMS simulator with ADE, you can load and use any state file that ADE has saved, regardless of the simulator ADE was running when the state file was saved. Other simulators include Virtuoso^® Spectre, Virtuoso^® APS, and Virtuoso^® XPS-MS.
• Available analyses
  Transient, AC, DC, and noise analyses are available when you use the AMS simulator and Spectre or APS solver with ADE. (When you use the AMS simulator with XPS-MS solver, only transient analysis is available.) You can save the DC operating point.
• Outputs
  You can use the ADE Output options to Save All Signals or to Select Specific Signals. You cannot save AC currents.
• Single Button Netlist and Run
  Netlisted files must be compiled and elaborated before they can be simulated. When you press Netlist and Run, a sequence of tools, including the simulator, is invoked.
  • Schematics and layout views are translated to Verilog-AMS structural netlists
  • Netlists are compiled
  • Elaboration runs
  • Simulation runs
  
  Each tool produces a separate log file. When any tool fails, the CIW displays a failure message. Look in the log file of the tool for descriptive error messages. The xrun.log file utilizes the error message and linked file hyperlinking feature enabling a quicker debug process.
• Full support for ADE display tools
  The integration of the AMS simulator and ADE makes the full set of ADE tools available. In particular, you can examine waveforms with the Virtuoso Visualization and Analysis XL display tools and take advantage of their superior performance for large mixed-signal designs as well as their analog-centric capabilities. You can backannotate DC and transient operating point information to the schematic. You can use ADE data access features such as the Calculator and Results Browser, and the ADE Direct Plot form.
• Full support for Incisive Simvision Debug tools
  The integration of the AMS simulator and ADE makes the full set of Simvision tools available. In particular, you can examine waveforms with the Incisive Simvision display tools and take advantage of their superior capability and performance for large mixed-signal designs as well as Simvision digital-centric debug capabilities. You can run your simulation in Simvison Interactive mode for real-time simulation results and text-based model debugging, such as the Calculator and Results Browser, and the ADE Direct Plot form.
• Support for running the simulator interactively
  This feature launches SimVision and provides you the ability to cross-probe from the schematic.
• OCEAN
  Ocean provides full support for the AMS simulator including several new commands such as connectRules().
• Distributed simulation
  Use network mode for distributed AMS simulations.
• Visual display of signal and cellview domains
  In the schematic window, you can highlight analog nets and digital nets in different colors, with indicators showing the mixed-signal domain and location of automatically inserted connect modules. Visualization of a mixed-signal design can help you tune the design for desired characteristics.
• Graphical support for viewing and manipulating global signals
  You can see the global signals that are extracted from the schematic design after netlisting or add new global signals that are found only in text views.
• Graphical support for disciplines and connect rules
  With the Select Connect Rules form, you can create new disciplines, customize connect rules, and select the connect rules to be used during simulation.
• Support for specifying block-based discipline resolution (BDR)
  You can suggest a discrete discipline to be used for a net, terminal, instance terminal, instance, cell, or library, thereby influencing the connect modules that are used during simulation.
• Graphical support for IE card setup
  The new IE Card Setup GUI enables you to automate the process of creating custom discrete disciplines to enable connect rule/connect module creation and placement specifically improving the usability of AMS multi-supply design configurations. The new IE card setup GUI provides a single place where you can configure your connect rules and connect modules, specify the scope for the built-in ie cards, and set or change the values of important ie card parameters, such as vsup, tr, tf, rout, and so on through an intuitive and easy-to-use GUI selection.
• AMS Unified Netlister (AMS UNL)
  AMS UNL provides a comprehensive netlisting and binding framework for the AMS Designer Virtuoso Use Model (AVUM) flow. It enables you to seamlessly migrate from the OSSN-based xrun netlisting flow. It also provides enhanced benefits for the existing OSSN users. AMS UNL natively parses SystemVerilog, VHDL-AMS, and VerilogAMS text-based models. It utilizes the xrun external text referencing capabilities that allow better text integration and seamless migration with xrun digital-based flows. VHDL and VHDL-AMS designs are fully supported in the AMS UNL flow.
• Xcelium xrun integration
  The “one step” xrun digital simulator is available in AMS in ADE. The xrun use model is similar to ncverilog and works seamlessly with the -y/-v/-f options. This approach is more consistent with the digital use model allowing design information to be more conveniently shared between digital and analog teams.
• AMS/Matlab

AMS/Matlab is officially supported. A Pcell coupler module has been added to analogLib and a utility is available which allows a user to create fixed coupler cells. There are three possible flows that a user can choose from:

• • An ADE integration where the user can launch Matlab from ADE.
  • The use model of starting Matlab and ADE separately is still supported.
  • The user can start Matlab and then can start AMS (via a run script).

For ADE Users: Differences to Expect When Using AMS in ADE

Some significant differences introduced with the AMS integration and ADE are the following.

• AMS Unified Netlister flow (AMS UNL) provides seamless migration from the OSSN-based netlisting flow. AMS UNL will become the single supported flow in ADE once all legacy migrations have taken place by customers. The plan is to deprecate the OSSN flow once this is complete
• Both the Netlist command and the Netlist and Run command can potentially call several tools to
  • Compile updated text views
  • Netlist updated schematic cellviews
  • As necessary, call xrun to compile, elaborate, and simulate
  
  Messages in the CIW indicate which tool is running. Each tool writes its own log file.
• The NCBrowse utility helps pinpoint issues in the logfiles created during compilation, elaboration and simulation. Use Simulation – Output Log – LogFile Utility to run the NCBrowse utility.
• By default, AMS in ADE does not save outputs. In the ADE Simulation window, do one of the following
  • Select Outputs – Save All to save all output signals.
  • Select Outputs – To Be Saved – Select On Design and select specific output signals.

For AMS Users: Differences to Expect When Using AMS in ADE

• ADE state files are used.
  • The ADE default mechanism is used. The .cdsenv file provides all ADE defaults.
  • The ams.env file is not used. Any defaults you set using the AMS Designer mechanism are not used.
    The ams.env file or its variables are not supported for AMS UNL.
• To specify an hdl.var file to be used, select Simulation – Options – Compiler to open the Compiler Options window. Then, in the hdl.var file field, specify the file you want to use. If you do not explicitly specify an hdl.var file in this way, then the hdl.var file will not be used for your ADE session.

Where to Get More Information

For more information, see the following documents

• • Select Session – FAQ in the Simulation window to display a list of solutions to frequently asked questions.
  • The Virtuoso Analog Design Environment User Guide
  • The Virtuoso AMS Simulator User Guide
  • The Cadence Hierarchy Editor User Guide
  • The Cadence Application Infrastructure User Guide

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