PTM-ET Release Notes

PTM-ET 2017-RC06(beta)

New functionality compared to ptm-5.3

  • Automatic generation of RSPEC (for linear mode) from the table model Ids(Vds, Vgs,T) for a given bias condition. This also implies that the ambient temperature can be changed to get the appropriate specific resistance.
  • A documented subset of Magwel’s software functionality can be accessed through an Application Programming Interface (API). This enables customization of technology file generation by CAD/PDK teams. An interface is available to access some of the functionality from standard scripting languages. Interfaces to three different scripting languages are foreseen: perl, python and tcl. The Magwel software installation comes with its own version of these interpreters.

perl: version 5.8.9
python: version 2.4.4
tcl: version 8.4.13

  • Improved CADENCE integration. The tool can be started within the CADENCE Virtuoso 6.1 framework; fields and hotspots can be reported back to this framework.
  • Excitations (stimuli) can be saved and reloaded for a given setup. The file containing the stimuli can be manually/automatically generated.
  • Re-use of mesh. User can save the mesh and re-loaded in a subsequent simulation possibly with changed stimuli provided that the structure has not changed.
  • Multiple devices handling. It is possible to run designs, which contain multiple devices. These devices can be of different type and the excitation (e.g. gate voltage) can be separately specified.
  • New non-linear RDSON mode. This mode enables the user to model the active devices by a non-linear table of Ids(Vds,Vgs,T) derived from a Spice/Spectre level simulation. Critical to model accurately LDOs and other devices that are sensitive to changes of Vgs over the active area. The gate voltage can be changed on the fly to switch to  another operating point without need for new GDS import.
  • Support for automatic creation of nonlinear table models from a Spectre deck using customer’s device models.
  • Various bug fixes and performance enhancements

Important: Flexlm upgrade

This version works with an upgraded version of lmgrd and MAGWELD, using version 11.14. You can find both files in the package in the flexNet directory.

Known problems and solutions

Crash when running it on Centos 7.3 (#5084) containing a newer libfontconfig version.

  • Solution: Remove libfontconfig lib from the installation, such that the system libs are used.
    • PROMPT> cd $MAGWELDIR/lib
    • PROMPT> rm libfontconfig*

Gate delay simulations ran with ptm-5.3 will not open in ptm-2017.

  • Solution: rerun the gate delay simulation in ptm-2017.

When more than one device with multiple stimuli in simulation, the total R value reported in rds_results.csv is not well-defined. The equivalent R does obey conservation of energy:

In the RDSon Non-linear mode simulation (without Rspec value in widget view), while change simulation temperature, an error message will pop up as: “Rspec value should be a number. Please enter a positive value.”

  • Solution: set the temperature, press OK, ignore above error message and close the window.  Then re-open the same window. The correct temperature is set. Proceed as usual. The tool actually uses the new temperature value.

When PTM is integrated in Cadence Virtuoso, there is an option to view current density violations from annotated virtuoso layout window by choosing “Magwel Tools -> View Results”.  If the original virtuoso layout window is closed before the EM violation window, the view results option will be grayed out.

  • Solution: restart Virtuoso

When PTM is integrated in Cadence Virtuoso, the EM violations are annotated in a Virtuoso layout window.  A filled box marks each violation. This can be confusing some times. Always check original layout window for real layout.  Annotations do not change layout.