PSpice User Guide

PSpice User Guide Convergence and "time step too small errors" October 2019 854 Product Version 17.4-2019 © 1999-2019 All Rights Reserved.

• Cover
• Contents
• Before you begin
• Welcome
• Comparison of PSpice Tiers
• How to use this guide
• Symbols and conventions
• Related documentation
• PSpice Samples and Tutorials
• Part one: Simulation primer
• Things you need to know
• Chapter overview
• What is PSpice?
• Analyses you can run with PSpice
• Basic analyses
• Advanced multi-run analyses
• Analyzing waveforms with PSpice
• What is waveform analysis?
• Using PSpice with other programs
• Using design entry tools to prepare for simulation
• What is the PSpice Stimulus Editor?
• What is the PSpice Model Editor?
• Files needed for simulation
• Files that design entry tool generates
• Other files that you can configure for simulation
• Files that PSpice generates
• Directory structure for analog projects in Capture
• How are files configured at the design level maintained in the directory structure for analog projects?
• How are files configured at the profile level maintained in the new directory structure for analog projects?
• What happens when I convert an analog project that uses a design from another project or from another location?
• What should I do if the schematic for a converted analog project uses FILESTIMn parts from the SOURCE library?
• Design Entry HDL libraries
• Reference Libraries
• Local libraries
• PSpice model libraries
• The cds.lib file
• Encrypting PSpice Models
• Using PSpiceEnc
• Using Model Editor
• Simulation examples
• Chapter overview
• Example circuit creation
• Using Capture
• Using Design Entry HDL
• Using Design Templates
• Finding out more about setting up your design
• Running PSpice
• Performing a bias point analysis
• Using the simulation output file
• Finding out more about bias point calculations
• DC sweep analysis
• Setting up and running a DC sweep analysis
• Displaying DC analysis results
• Finding out more about DC sweep analysis
• Transient analysis
• Finding out more about transient analysis
• AC sweep analysis
• Setting up and running an AC sweep analysis
• AC sweep analysis results
• Finding out more about AC sweep and noise analysis
• Parametric analysis
• Setting up and running the parametric analysis
• Analyzing waveform families
• Finding out more about parametric analysis
• Performance analysis
• Finding out more about performance analysis
• Part two: Design entry
• Preparing a design for simulation
• Chapter overview
• Checklist for simulation setup
• Typical simulation setup steps
• Advanced design entry and simulation setup steps
• When netlisting fails or the simulation does not start
• Using parts that you can simulate
• Vendor-supplied parts
• Passive parts
• Breakout parts
• Behavioral parts
• Simulating asymmetric parts in PSpice
• Simulating homogeneous parts in PSpice
• Specifying values for part properties
• Using global parameters and expressions for values
• Global parameters
• Expressions
• Defining power supplies
• For the analog portion of your circuit
• For A/D interfaces in mixed-signal circuits
• Defining stimuli
• Analog stimuli
• Digital stimuli
• Things to watch for
• Unmodeled parts
• Unconfigured model, stimulus, or include files
• Unmodeled pins
• Missing ground
• Missing DC path to ground
• Creating and editing models
• Chapter overview
• What are models?
• How are models organized?
• Model libraries
• Model library configuration
• Global vs. design vs. profile models and libraries
• Nested model libraries
• PSpice-provided models
• Model library data
• Device characteristic curves-based models vs. Template-based models
• Tools to create and edit models
• Ways to create and edit models
• Using the Model Editor
• Ways to use the Model Editor
• Running the Model Editor alone
• Starting the Model Editor
• Creating models using the Model Editor
• Creating models based on device characteristic curves
• Creating models based on PSpice templates
• Importing an existing model
• Enabling and disabling automatic part creation
• Running the Model Editor from the schematic editor
• Model creation examples
• Example: Creating a PSpice model based on device characteristic curves
• Example: Creating template-based PSpice model
• Editing model text
• Example: editing a Q2N2222 instance model
• Using the Create Subcircuit Format Netlist command (Capture only)
• Changing the model reference to an existing model definition
• Reusing instance models
• Reusing instance models in the same schematic
• Making instance models available to all designs
• Configuring model libraries
• The Configuration Files tab
• How PSpice uses model libraries
• Adding model libraries to the configuration
• Changing the model library scope from profile to design, profile to global, design to global and vice versa
• Changing model library search order
• Changing the library search path
• Handling smoke information using the Model Editor
• Adding smoke information to PSpice models
• Creating template-based PSpice models with smoke information
• Using the Model Editor to edit smoke information
• Examples: Smoke
• Adding smoke information to the D1 diode model
• Adding smoke information to the OPA_LOCAL operational amplifier model
• Smoke parameters
• Diode
• Bipolar Junction Transistors
• Magnetic Core
• Ins Gate Bipolar Transistor (IGBT)
• Junction FET
• Operational Amplifier
• MOSFET
• Voltage Regulator
• Darlington Transistor
• Creating parts for models
• Chapter overview
• What's different about parts used for simulation?
• Ways to create parts for models
• Preparing your models for part creation
• Starting the Model Editor
• Using the Model Editor to create parts
• Batch mode of part creation
• Interactive mode of part creation
• Creating Design Entry Tool parts for all models in a library
• Using batch mode
• Using interactive mode
• Setting up automatic part creation
• Example
• Creating parts in the batch mode
• Creating parts using interactive mode
• Basing new parts on a custom set of parts
• Editing part graphics (Capture only)
• How Capture places parts
• Defining grid spacing
• Attaching models to parts
• MODEL
• Defining part properties needed for simulation
• PSPICETEMPLATE
• IO_LEVEL
• MNTYMXDLY
• PSPICEDEFAULTNET
• Analog behavioral modeling
• Chapter overview
• Overview of analog behavioral modeling
• The ABM part library file
• Placing and specifying ABM parts
• Net names and device names in ABM expressions
• Forcing the use of a global definition
• ABM part templates
• Control system parts
• Basic components
• Limiters
• Chebyshev filters
• Integrator and differentiator
• Table look-up parts
• Laplace transform part
• Math functions
• ABM expression parts
• An instantaneous device example: modeling a triode
• PSpice-equivalent parts
• Implementation of PSpice-equivalent parts
• Modeling mathematical or instantaneous relationships
• Lookup tables (ETABLE and GTABLE)
• Frequency-domain device models
• Laplace transforms (LAPLACE)
• Frequency response tables (EFREQ and GFREQ)
• Cautions and recommendations for simulation and analysis
• Instantaneous device modeling
• Frequency-domain parts
• Laplace transforms
• Trading off computer resources for accuracy
• Basic controlled sources
• Creating custom ABM parts
• Digital device modeling
• Chapter overview
• Introduction
• Functional behavior
• Timing characteristics
• Timing model
• Propagation delay calculation
• Inertial and transport delay
• Input/Output characteristics
• Input/Output model
• Defining Output Strengths
• Charge storage nets
• Creating your own interface subcircuits for additional technologies
• Creating a digital model using the PINDLY and LOGICEXP primitives
• Digital primitives
• Logic expression (LOGICEXP primitive)
• Pin-to-pin delay (PINDLY primitive)
• BOOLEAN
• PINDLY
• Constraint checker (CONSTRAINT primitive)
• Setup_Hold
• Width
• Freq
• 74160 example
• Part three: Setting up and running analyses
• Setting up analyses and starting simulation
• Chapter overview
• Analysis types
• Setting up analyses
• Order for standard analyses
• Output variables
• Setting AutoConvergence
• Using Advanced Analog Options
• Performance package
• Starting a simulation
• Creating a simulation netlist
• Starting a simulation from a Design Entry Tool
• Starting a simulation outside of Design Entry Tool
• Setting up batch simulations
• The PSpice simulation window
• Interacting with a simulation
• Extending a transient analysis
• Interrupting a simulation
• Scheduling changes to runtime parameters
• Setting Autoconvergence from the Runtime Settings Dialog Box
• Using the Simulation Manager
• Overview of the Simulation Manager
• Setting up multiple simulations
• Starting, stopping, and pausing simulations
• Attaching PSpice to a simulation
• Setting options in the Simulation Manager
• DC analyses
• Chapter overview
• DC Sweep
• Minimum requirements to run a DC sweep analysis
• Overview of DC sweep
• Setting up a DC stimulus
• Nested DC sweeps
• Curve families for DC sweeps
• Bias point
• Minimum requirements to run a bias point analysis
• Overview of bias point
• Small-signal DC transfer
• Minimum requirements to run a small-signal DC transfer analysis
• Overview of small-signal DC transfer
• DC sensitivity
• Minimum requirements to run a DC sensitivity analysis
• Overview of DC sensitivity
• AC analyses
• Chapter overview
• AC sweep analysis
• Setting up and running an AC sweep
• What is AC sweep?
• Setting up an AC stimulus
• Setting up an AC analysis
• AC sweep setup in example.opj
• How PSpice treats nonlinear devices
• Noise analysis
• Setting up and running a noise analysis
• What is noise analysis?
• Setting up a noise analysis
• Analyzing Noise in the Probe window
• Parametric and temperature analysis
• Chapter overview
• Parametric analysis
• Minimum requirements to run a parametric analysis
• Overview of parametric analysis
• RLC filter example
• Example: frequency response vs. arbitrary parameter
• Temperature analysis
• Minimum requirements to run a temperature analysis
• Overview of temperature analysis
• Transient analysis
• Chapter overview
• Overview of transient analysis
• Minimum requirements to run a transient analysis
• Defining a time-based stimulus
• Overview of stimulus generation
• Using CheckPoints
• Specifying CheckPoints
• Restarting Simulation from a Saved CheckPoint
• The Stimulus Editor utility
• Stimulus files
• Configuring stimulus files
• Starting the Stimulus Editor
• Defining stimuli
• Creating new stimulus symbols
• Editing a stimulus
• Deleting and removing traces
• Manual stimulus configuration
• Finding out more about the Stimulus Editor
• Transient (time) response
• Internal time steps in transient analyses
• Switching circuits in transient analyses
• Plotting hysteresis curves
• Fourier components
• Monte Carlo and sensitivity (worst-case) analyses
• Chapter overview
• Statistical analyses
• Overview of statistical analyses
• Output control for statistical analyses
• Model parameter values reports
• Monte Carlo history support
• Waveform reports
• Collating functions
• Temperature considerations in statistical analyses
• Monte Carlo analysis
• Example: Monte Carlo analysis of a pressure sensor
• Monte Carlo Histograms
• Worst-case analysis
• Overview of worst-case analysis
• Worst-case analysis example
• Tips and other useful information
• Digital simulation
• Chapter overview
• What is digital simulation?
• Steps for simulating digital circuits
• Concepts you need to understand
• States
• Strengths
• Defining a digital stimulus
• Using the DIGSTIMn part
• Defining input signals using the Stimulus Editor
• Using the DIGCLOCK part
• Using STIM1, STIM4, STIM8 and STIM16 parts
• Using the FILESTIMn parts
• Defining simulation time
• Adjusting simulation parameters
• Selecting propagation delays
• Initializing flip-flops
• Starting the simulation
• Analyzing results
• Adding digital signals to a plot
• Adding buses to a waveform plot
• Tracking timing violations and hazards
• Mixed analog/digital simulation
• Chapter overview
• Interconnecting analog and digital parts
• Interface subcircuit selection by PSpice
• Level 1 interface
• Level 2 interface
• Setting the default A/D interface
• Specifying digital power supplies
• Default power supply selection by PSpice A/D
• Creating custom digital power supplies
• Interface generation and node names
• Digital worst-case timing analysis
• Digital worst-case timing
• Digital worst-case analysis compared to analog worst-case analysis
• Starting digital worst-case timing analysis
• Simulator representation of timing ambiguity
• Propagation of timing ambiguity
• Identification of timing hazards
• Convergence hazard
• Critical hazard
• Cumulative ambiguity hazard
• Reconvergence hazard
• Glitch suppression due to inertial delay
• Methodology
• Part four: Viewing results
• Analyzing waveforms
• Chapter overview
• Overview of waveform analysis
• Elements of a plot
• Elements of a Probe window
• Managing multiple Probe windows
• Setting up waveform analysis
• Setting up colors
• Viewing waveforms
• Setting up waveform display from design entry tools
• Viewing waveforms while simulating
• Using schematic page markers to add traces
• Using display control
• Using plot window templates
• Limiting waveform data file size
• Viewing large data files
• Using simulation data from multiple files
• Comparing measured data with simulated data
• Saving simulation results in ASCII format
• Analog example
• Mixed analog/digital tutorial
• About digital states
• About the oscillator circuit
• Setting up the design
• Running the simulation
• Analyzing simulation results
• User interface features for waveform analysis
• Zoom regions
• Scrolling traces
• Showing and hiding traces
• Sizing digital plots
• Modifying trace expressions and labels
• Moving and copying trace names and expressions
• Copying and moving labels
• Tabulating trace data values
• Using cursors
• Tracking digital simulation messages
• Message tracking from the message summary
• Message tracking from the waveform
• Trace expressions
• Basic output variable form
• Output variable form for device terminals
• Analog trace expressions
• Digital trace expressions
• Measurement expressions
• Chapter overview
• Measurements overview
• Measurement strategy
• Procedure for creating measurement expressions
• Setup
• Composing a measurement expression
• Viewing the results of measurement evaluations
• Example
• Viewing the results of measurement evaluations.
• Measurement definitions included in PSpice
• For power users
• Creating custom measurement definitions
• Definition example
• Measurement definition syntax
• Syntax example
• Other Output Options
• Chapter overview
• Viewing analog results in the PSpice window
• Writing additional results to the PSpice output file
• Generating plots of voltage and current values
• Generating tables of voltage and current values
• Generating tables of digital state changes
• Creating test vector files
• Exporting Trace to CSV File
• Bias Point Display
• Introduction
• How bias information is stored and updated
• Bias point data for multiple analyses
• Displaying bias point values
• Controlling the display of bias points
• Moving bias points
• Updating bias point values
• Menu commands for bias point display
• Toolbar controls for bias point display
• Toggling a specific current bias display
• Toggling a specific voltage bias display
• Toggling a specific power bias display
• Setting initial state
• Appendix overview
• Save and load bias point
• Save bias point
• Load bias point
• Setpoints
• Setting initial conditions
• Convergence and "time step too small errors"
• Appendix overview
• Introduction
• Newton-Raphson requirements
• Is there a solution?
• Are the equations continuous?
• Is the initial approximation close enough?
• Diagnostics
• Bias Point (DC) Convergence
• DC Sweep Convergence
• Transient Convergence
• Importing Spice Models
• Appendix Overview
• Introduction
• Importing text models
• Generating Part Symbols
• Creating New Symbols
• Using symbols from an existing symbol library
• Using Model Import wizard
• Configuring new model library
• Editing Model Editor created symbols
• Index