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

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:



Threads

• 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 options—biaspoint convergence

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

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

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

New PSpice options—transient convergence

• METHOD = [TRAPEZOIDAL|GEAR|DEFAULT]
  • Integration method to be used during Transient analysis
  • Gear is more stable, so more often used in the default mode
  • Trapezoidal is more accurate
• TRTOL
  • 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
• LIMIT
  • 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
• WCDEVIATION
  • 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 options—accuracy

• PROBE64
  • 64-bit probe data
  • Increases resolution of probe
  • Very useful for differential probes
• NOGMINI
  • Suppress GMIN addition across current sources
  • Gives more accurate results for very low current values
• BRKDEPSRC
  • 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