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Computer Aided Design

Computer Aided Design. Course 2. Spice. Simulation. Common File Extensions. .OPJ Capture project file .DSN Capture design file .OLB Capture part library file .UPD Property update file .DRC Design rules check file .BOM Bill of Materials file .EXP Export properties file.

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Computer Aided Design

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  1. Computer Aided Design Course 2

  2. Spice Simulation

  3. Common File Extensions .OPJ Capture project file .DSN Capture design file .OLB Capture part library file .UPD Property update file .DRC Design rules check file .BOM Bill of Materials file .EXP Export properties file .MNL Layout netlist file .SWP Layout backannotation file .XRF Cross-reference report .NET or .ASC Other netlist files .VHD or .VHO VHDL source file .EDF EDIF 2.0 netlist

  4. Project Manager Window

  5. Schematics Editing steps • Start a new project, select “Analog or Mixed A/D” (enables PSpice) • Create a new directory to hold the files and provide a descriptive file name • Create the project • Add the PSpice library (ex. “analog.olb”) • Build and wire the circuit • Annotate • Run Design Rules Check (DRC) • Build Bill of Materials (BOM) • Print

  6. Automatic Reference Designator Assignment

  7. Design Rules Check

  8. Create BOM to List Footprints

  9. PSpice Analysis Flow

  10. New Simulation Profile

  11. Simulation Settings Menu

  12. Enable bias voltage display Enable power display Enable bias currents display Bias Point Display

  13. BASIC PART ABBREVIATIONS Resistor R capacitor C current-controlled current source F current-controlled voltage source H ground, analog AGND voltage-controlled current source G voltage-controlled voltage source E Simple voltage source VAC Transient sine voltage source VSIN

  14. Analog stimuli The analog stimuli symbols available in Schematics are:

  15. *. VSTIM and ISTIM symbols require the Stimulus Editor to define the input signal. • **. FILE-BASED Symbols: VPWL_F_RE_FOREVER and VPWL_F_N_TIMES are file-based symbols; the stimulus specification resides in a file and adheres to PSpice netlist syntax. • To determine the symbol name for an equivalent Current source • In the table of voltage source symbols, replace the first V in the symbol name with I (Example: VDC -> IDC).

  16. Stimulus Symbols for Analog Time-Based Input Signals

  17. Defining Stimulus Symbol Attributes Manually in Schematics To use any of these source types, you must place the symbol in your schematic and then define its transient behavior. Each attribute-characterized stimulus has a distinct set of attributes depending upon the kind of transient behavior it  represents. For VPWL_F_xxx and IPWL_F_xxx, a separate file contains the stimulus specification. Defining VSTIM or ISTIM using the Stimulus Editor

  18. As an alternative, the Stimulus Editor utility automates the process of defining the transient behavior of stimulus devices. The Stimulus Editor allows you to create analog stimuli which generate sine wave, repeating pulse, exponential pulse, single-frequency FM, and piecewise linear waveforms. It also facilitates creating digital stimuli with complex timing relations. This applies to both stimulus symbols placed in your schematic as well as new ones that you might create.

  19. Stimulus Editor

  20. HOW DOES SPICE WORK? Basically, SPICE operates like this: 1. Describe a circuit in a text file (“.cir” extension) called a netlist OR draw the circuit using graphical symbols on a schematic page. 2. Run a simulation. SPICE reads the netlist and then performs the requested analysis: AC, DC, or TRANSIENT RESPONSE. The results are stored in a text output file (“.out” extension) or a binary data file. 3. View the results of the simulation in a text output file ( “.out” ) using a text editor. Most SPICE programs provide a graphical viewer to plot the waveforms stored in the binary data file (Probe window).

  21. Netlist File * source CIRC1 V_V1 N00129 0 +SIN 0 1 1k 0 0 0 R_R1 N00129 N00138 1k L_L1 N00138 N00145 10uH C_C1 0 N00145 1n

  22. NETLIST OR SCHEMATIC PAGE? Although, the schematic capture has its advantages, each SPICE vendor has a different drawing interface and file format. This would cause great confusion if you used a version of SPICE different from the one used at this site. Also, the learning curve for the schematic capture can be steep. Many component characteristics are not visible from the schematic. (Ultimately, the schematic capture program creates a netlist before running a simulation.)

  23. NETLIST OR SCHEMATIC PAGE? The netlist description of a circuit is simple and fairly consistent for each SPICE vendor with some variations. The entire circuit and component properties are visible. Learning the netlist is easy and making changes is fast. You can create a netlist by drawing the circuit on paper and applying a few simple rules. (Several books written on SPICE strongly recommend learning the netlist, even if you decide later to use a schematic capture program.)

  24. NETLIST

  25. NETLIST

  26. Output File **** 03/05/06 16:06:27 ******* PSpice 10.3.0 (Jan 2004) ******* ID# 1111111111 ** Profile: "SCHEMATIC1-circ1" [ C:\ORCAD_DATA\CAD\circ1-PSpiceFiles\SCHEMATIC1\circ1.sim ] **** CIRCUIT DESCRIPTION ****************************************************************************** ** Creating circuit file "circ1.cir" ** WARNING: THIS AUTOMATICALLY GENERATED FILE MAY BE OVERWRITTEN BY SUBSEQUENT SIMULATIONS *Libraries: * Profile Libraries : * Local Libraries : * From [PSPICE NETLIST] section of C:\OrCAD\OrCAD_10.3\tools\PSpice\PSpice.ini file: .lib "nom.lib"

  27. Output File - 2 *Analysis directives: .TRAN 0 10ms 0 .PROBE V(alias(*)) I(alias(*)) W(alias(*)) D(alias(*)) NOISE(alias(*)) .INC "..\SCHEMATIC1.net" **** INCLUDING SCHEMATIC1.net **** * source CIRC1 V_V1 N00129 0 +SIN 0 1 1k 0 0 0 R_R1 N00129 N00138 1k L_L1 N00138 N00145 10uH C_C1 0 N00145 1n **** RESUMING circ1.cir **** .END

  28. Output File - 3 **** 03/05/06 16:06:27 ******* PSpice 10.3.0 (Jan 2004) ******* ID# 1111111111 ** Profile: "SCHEMATIC1-circ1" [ C:\ORCAD_DATA\CAD\circ1-PSpiceFiles\SCHEMATIC1\circ1.sim ] **** INITIAL TRANSIENT SOLUTION TEMPERATURE = 27.000 DEG C ****************************************************************************** NODE VOLTAGE NODE VOLTAGE NODE VOLTAGE NODE VOLTAGE (N00129) 0.0000 (N00138) 0.0000 (N00145) 0.0000 VOLTAGE SOURCE CURRENTS NAME CURRENT V_V1 0.000E+00 TOTAL POWER DISSIPATION 0.00E+00 WATTS

  29. Output File - 4 JOB CONCLUDED **** 03/05/06 16:06:27 ******* PSpice 10.3.0 (Jan 2004) ******* ID# 1111111111 ** Profile: "SCHEMATIC1-circ1" [ C:\ORCAD_DATA\CAD\circ1-PSpiceFiles\SCHEMATIC1\circ1.sim ] **** JOB STATISTICS SUMMARY ****************************************************************************** Total job time (using Solver 1) = .19

  30. Probe window

  31. Probe window

  32. Probe window

  33. Probe window

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