Cadence PCB Design Blogs

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What's Good About Allegro AMS New Advanced Options? They're in the 16.6 Release! Posted: 26 Feb 2013 09:47 AM PST The Allegro AMS Simulator (analog/mixed-signal) 16.6 release adds several enhancements to the Advanced Options dialog form. This enables the customizability of a PSpice simulation run, including control over convergence homotopy options, making worst-case analysis independent of RELTOL and enabling auto-convergence automatically in case of convergence failure. These options do not change the core behavior of the simulator, but provide the designer new ways to control the behavior at different simulation points. Options have been added to the Advanced Analysis Options dialog box in the following areas: --Bias-Point Convergence --Integration Method --Voltage Limiting --Worst-case Deviations --Max-Time Step Control --Pseudo Transient --Relative Tolerance Read on for more details… Here are the new options available in the Advanced Analog Options form:   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 For the 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 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 For the 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 fastswitching designs Default = 7 There are also new PSpice Options: 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 * WCDEVIATION 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 I look forward to your feedback! Jerry "GenPart" Grzenia