4. Prepare For Simulation In Accusim

1. Again, from the Design Architect, display the MGC Analog Libraries palette by selecting from the main menu bar:
   Libraries -> MGC Analog Libraries -> Display Libraries Palette

2. Select Analog M/S Utilities -> Create Viewpoint from the palette. A dialog box as shown in Fig. 4-1 will appear. Enter the model filename that you created earlier in section 3 to the 'Netlistfile' field.

3. For the "Library Directory" field, enter the path name that contains the model file you specified in previous step. Then click on "OK".

   Note: If you don't specify the model file, "Create Viewpoint" function will try to search file with extension ".mod", ".ckt",".sub" in the Library Directory you specified for your model definition.

   

   Figure 4-1. Create Design Viewpoint for AccuSim.

   After a couple of seconds, a message "Viewpoint created successfully" will appear at the bottom of the window.

5. Simulation In Accusim

Note: Post-Layout simulation after parameters back annotated from ICextract do exactly the same steps listed below.
• In the Design Manager tools window, double-click on the "Accusim" icon to invoke the simulator.
• A dialog box will appear. Enter the complete path and viewpoint name created in previous section for the schematic you will be simulating.
• Accusim II window will be open along with your design.

5.1 Time Transient Analysis

1. Select from the main menu bar:
   Setup -> Analysis...

   A dialog box as shown in Fig 5-1 will appear . Click on 'Transient' for time transient analysis. Enter '0.1n' for 'Time Step' box and '20n' for 'Stop Time' field. Then click on 'OK'.

   

   Figure 5-1. Setup analysis to time transient analysis.

2. There are two ways to give test signal to input ports; the first way is to assign input signals right in Accusim, and the other way is to specify the input signals in a file.
   • To assign input signal in Accusim, select 'in' port from the schematic. Then click on 'ADD FORCE' from the 'Time Mode' palette. A 'Force' dialog box will appear as shown in Fig 5-2.

     

     Figure 5-2. Force input dialog box.

     Click on 'PULSE' to form a test signal. Activate 'View Force', then enter pulse parameters for the rest of the field as shown in Fig 5-2. Click on "OK"

   • To specify input signals in a file: The format for input signals file is exactly the same as PSPICE syntax. Say, you have a file named "input1.sig" with input signal as following: (Note that lines starting with "*" will be considered as comment lines.)

     
     ******** Input signal "in"  with period 10ns ****************** 
     
     Vin in 0 pulse(0 5 5N 0.1N 0.1N 5N 10N)
     
     ******** Alternative for input signal "in" with period 20ns ***
     
     *Vin in 0 pulse(0 5 10N 0.1N 0.1N 10N 20N)
     
     

     Select from the main menu bar,
     File -> Auxiliary Files -> Load Netlistfiles...

     A "Load Netlistfile" dialog box will appear. Enter the complete path and input filename or use Navigator to locate "input1.sig".

3. If you are familiar with PSPICE netlist format, you can check the netlist before you run it by selecting from the main menu bar:
   Report -> Netlist

4. To probe circuit nodes, in the schematic window, select the ports/nets you will trace then click "Trace" on the right hand side palette. A trace window will be opened.

5. To run your circuit, click on 'Run' icon from the right side palette. A box 'Add keeps' will appear. Click on 'OK'. To interrupt a running task, press CTRL-c to stop it (Note: lower case 'c').

6. It takes a couple of seconds to run the simulation. The result is shown in Fig. 5-3.

   

   Figure 5-3. Add simultion result waveform to input waveform chart.

7. To obtain the 50% propagation delay from the waveform, say, the 50% propagation delay from the input to output for edges between 4ns and 8ns follow the steps given below.
   • In the schematic, first select the "in" port and then the "out" port. (Be carefull about the order of selection).

   • Click "WF MEASURE" on the "Result" palette. A pop-up menu will appear.

   • Select "Delay Time:", A dialog bar will appear at the bottom of the window as shown in Fig.5-3a.

     

     Figure 5-3a. Dialog bar for delay time measure

   • Click on "Options...". Enter "4n" in the "Start*" field and "8n" in the "Stop*" field for both A and B domains in the "Report Delay Options" dialog box as shown in Fig 3-5b below.

     

     Figure 5-3b. Report delay options dialog box

   • The 50% propagation delay will be reported at the bottom of the window.

8. Other timing information can also be obtained by using "WF MEASURE" on the "Result" palette.

9. It can be possible to get average power and instantaneous power from "WF FUNCTION" on the "Result" palette.After run for transient analysis,select all schematic and from main menu bar "Add->Keeps" all selected schematic,Run again.
   • AVERAGE POWER:
     • Click "WF FUNCTION" on the "Result" palette.A pop-up menu will appear.

     • Select "Power", a dialog box "Chart Power" will appear as shown in Fig. 5-4a.

       

       Figure 5-4a.Chart Power Dialog box

     • Select "Average Power" and chart to "New chart", click on "OK".

     • A dialog bar will pop-up as shown in fig. 5-4b.

       

       Figure 5-4b.Dialog bar for selecting location

     • A red cross line will appear on the schematic sheet.For this example ,move the mouse and place red cross line intersection at the power supply node VCC,click LMB.

     • The average power chart will appear as shown in fig. 5-4c.

       

       Figure 5-4c.Average Power Chart.

   • INSTANTANEOUS POWER:
     • Select WF Function -> "Power", a dialog box "Chart Power" will appear as shown same as in Fig. 5-4a.

     • Select "Instantaneous Power", then select chart to "New Chart", after that move a red cross line to VCC and click LMB, then it will create new chart window for power as shown in fig. 5-4d. Or its possible to draw a power chart superimpose on a selected chart, WF Function -> Power select "selected chart" in this case, it will create chart as shown in fig 5-4e.

     • All other procedures are same as AVERAGE POWER. Please read AVERAGE POWER first.

       

       Figure 5-4d.Instantaneous Power

       

       Figure 5-4e.Instantaneous Power with Output in same chart