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What's Good About AMS Multi-Core Engine Support? It’s in the 16.6 Release!

Comments(0)Filed under: AMS simulation, AMS simulator, Allegroro AMS Simulator (PSpice), AMS, pspice, Grzenia, Allegro 16.6, 16.6, Cadence, Cadence Design Systems

The 16.6 AMS Simulator (PSpice) release now includes support for multi-core capabilities. There are several runtime options available to enhance the performance of simulation runs.

Read on for more details…

Performance of multi-core capabilties is enabled. There are focused performance enhancements for large designs with complex model instances like MOSFETS and BJT. In addition, I/O performance improvements with significant performance enhancements for large DAT files are included:


  • Maximum number of threads to be used for simulation
    • THREADS = 1 => Single-threaded simulation
    • THREADS = 0 => Use default calculation
  • By default, the number of threads is calculated based on device count, number of cores in the machine, and the PSpice license used.
  • The default thread count is <= number of cores/2
  • A maximum of 4 threads can be used for regular PSpice licenses

Convergence improvement options

  • Advanced biaspoint convergence homotopies
  • Integration method option
  • Node value limiting
  • Relative tolerance
  • Accuracy improvement options
  • Worst-case control independent of RELTOL
  • Behavioral sources TimeStep control for sinusoidal functions
  • MinStep independent of TSTOP
  • 64-bit data accuracy

New PSpice optionsbiaspoint convergence

    • Bias-point convergence enhancement
    • Used when all other methods (STEPGMIN, STEPSOURCES) have failed
    • Enables all convergence algorithms, viz. PseudoTran, StepGmin, and StepSources (ON by default)
    • Enables StepGmin from inside of StepSources
    • Suppresses stepping of dependent sources during StepSources

Here are three options that give additional control to power users:

    • Maximum number of steps per iteration of StepGmin
  • ITL6
    • Maximum number of steps per iteration of StepSources
    • Maximum number of steps per iteration of PseudoTran

New PSpice optionstransient convergence

    • Integration method to be used during Transient analysis
    • Gear is more stable, so more often used in the default mode
    • Trapezoidal is more accurate
    • Tolerance for integration error calculated during transient analysis
    • A higher value implies more tolerance, so bigger time steps and reduced accuracy
    • Can be useful to jump model discontinuities in case of fast-switching designs
    • Default = 7
    • Absolute limit on data values calculated in PSpice engine during simulation
    • Can be used in case of overflow errors
    • Can also be useful for convergence failures in some simulations
    • Deviation to be used for worst-case analysis
    • Default calculation for worst-case delta is nominalValue * RELTOL
    • If WCDEVIATION is specified, it gets modified to nominalValue *

New PSpice optionsaccuracy

  • PROBE64
    • 64-bit probe data
    • Increases resolution of probe
    • Very useful for differential probes
    • Suppress GMIN addition across current sources
    • Gives more accurate results for very low current values
    • Sets automatic break-points for sinusoidal behavioral sources
    • Useful for long simulations when default Max Time Step is too big


New PSpice options—simulation enhancement

  • VT Tables
    • Optional parameter for table-driven behavioral sources
    • Tells simulator that x-axis of the table represents time
    • Run-time settings supports enabling convergence homotopies and configuration without a simulation re-start




As always, I look forward to your feedback!

Jerry “GenPart” Grzenia


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