6 Replies Latest reply on Apr 24, 2013 8:35 PM by Gary_Lameris

    DxDesigner / Hyperlynx Analog Top level


      Hello all,


      I am new here and this is my first post.

      I recently downloaded the DxDesigner/PADS evaluation SW since the company I work for will soon purchase the PADS suite.


      I tried the analog simulation on a schematic sheet and I was very pleased with its capabilities.

      However, when I put my schematic in a block to make a top level sheet and run it from there I get the message:


      "error - ground is an illegal node in schematic"


      This happens whether the block is created top-down or bottom-up.


      Fearing that there is something wrong with my schematic, I tried a very simple circuit, just one resistor, VCC and GND.

      The top level block has only the VCC and GND connections with the tool's special symbols.


      Any idea of what I do wrong?


      Thank you in advance

      George Giannopoulos

        • 1. Re: DxDesigner / Hyperlynx Analog Top level

          If you use the special symbols (power TAPS) then you don't need to propagate them through the hierarchy, they're seen as global, so they need only appear on the sheets that need them and they will be connected together. See Tech Note MG575950 on SupportNet for more information about global signals.

          • 2. Re: DxDesigner / Hyperlynx Analog Top level

            Thank you for the immediate response. I will try that.

            • 3. Re: DxDesigner / Hyperlynx Analog Top level

              As I go on with the evaluation, I have another question to ask:


              I see that there are a number of parameters that have to be defined in a symbol in order to use all the capabilities of the tool.

              That includes PCB decals, SPICE or IBIS models and a good number of other attributes.

              When my company buys the ES design suite, what libraries should I expect to have?


              In the evaluation version there is a tutorial that says how to import a SPICE model from a manufacturer's web site.

              But SPICE models are notorious for incompatibilities between versions, so a rich library of symbols accompanied with the right models would be something to wish for.

              Also IBIS models may be hard to find.


              What I wish to know is the actual effort that is needed, in the real world.

              I mean, if the library symbols come with their simulation models I will have to do nothing, if they don't but the models are available and compatible I will just have to assign them to the components, if they are not available I will have to take my chances with downloads from various manufacturers etc.


              Is there a listing or other examples that show how the libraries will be (e.g. through the DxDatabook) other than the specific libraries for the evaluation?

              • 4. Re: DxDesigner / Hyperlynx Analog Top level

                Check out the video http://www.mentor.com/products/pcb-system-design/multimedia/better-pcb-analog-design-webinar  It goes through most of your questions on a design similar to the design in the evaluation guide using the PADS ES suite.


                Hyperlynx Analog is designed as a block level simulator and not as a design level simulator of a PCB.   What this means is that you want to work in the block section of the Navigator in DxDesigner.   This frees you from some of the overhead of a PCB design, and allows the freedom to change values and explore opportunities to improve your design with simulation.  Once simulated, simply select the correct values for the design.   if the schematic block isn't visible in the Block section of the Navigator, you can create it safely with 4 simple steps.

                     1.  File backup sheet

                     2.  Add Block, and surround the circuit to be simulated

                     3.  Enter a valid name for the block and then extract schematic.  A block should be created

                     4.  go back to the top level page and File Rollback Sheet to restore the top level page exactly as you left it.


                Next...  Spice models

                     SPICE is an older simulator and requires many different properties that can conflict with designing a PCB.  To eliminate this issue, the SPICE properties are added with the Simulation Model Dialog.   (The properties can also be prepared on the symbol)   The Simulation Model Dialog also allows multiple models to be available in your design for each component, simply select the model to use for each simulation.


                Yes many manufacturer models are in PSPICE format.  We can translate traditional analog models into a format that is compatible with the HLA simulator.  Simply use the menu command Tools, Convert PSPice libraries.  The models that don't convert completely are the digital PSPICE models or those with the advanced non-standard lines containing math function lines like POLY.  Upgrading to our ELDO simulator will allow the math function lines  to translate, and as an added benefit the ELDO simulator is more than 10 times faster in getting results.


                The standard HLA library is delivered with 6500+ models and matching schematic symbols.  The symbols are not mated to a PADS decal with a part but you can map the model to your own symbols with the Simulation Model Dialog.  Coming soon are new enhancements to DxDesigner and PADS to make the process simpler to add simulation properties in your symbol and part library!

                • 5. Re: DxDesigner / Hyperlynx Analog Top level

                  Thank you very much.

                  I will experiment more based on this information.


                  By the way, your name sounds greek, are you?