Running Guardian LVS

001 : Running Guardian LVS

Minimum Required Versions: Expert 4.10.37.R, Guardian LVS 4.8.36.R

Guardian LVS (Layout Versus Schematic) netlist comparison tool compares two SPICE netlists. One of the compared netlists usually corresponds to the schematic of a circuit produced by a schematic editor (e.g. Gateway ), which represents the circuit. The other netlist is extracted from the circuit layout by Guardian NET . It represents the actual physical layout of the circuit as produced by a layout editor (e.g. Expert ).

1. Execution of Guardian LVS

1) Launch Guardian LVS from Expert by selecting Verification->LVS->Launch LVS .

2) It is necessary to se the project settings in the Project Settings dialog. To open it, select Setup->Project Settings or click the Project Settings button in the Action Toolbar .

3) Add two SPICE netlists to Input Files in the General tab. The netlist has to be set as follows:

Netlist #1 ----- Netlist of the schematic

Netlist #2 ----- Netlist of the layout

If the order of the two netlists is reversed, cross probing will not be executed.

4) To adjust the settings of a model, select the Models tab. You can either adjust the settings for a group of models (e.g., all MOS devices) or for a particular model of a specified device.

5) Then run LVS by selecting Run LVS from the Action menu or by clicking the Run LVS button in the Action Toolbar .

6) The LVS result is displayed in the LVS Log file.
Here is the example of the LVS result:

netlists are EQUIVALENT : two netlists are logically equivalent.

netlists are NOT EQUIVALENT : two netlists are not logically equivalent.

netlists are topologically EQUIVALENT, parameter errors are detected : two netlists are logically equivalent, but it has parameter errors.

netlists are topologically EQUIVALENT, label mismatch is detected : two netlists are logically equivalent, but it has a label mismatch error.

7) Details of the error are in the Unmatched file ( UM ) and Parameter Error file ( PE ) when there is an LVS error. When a node name (device name) in the UM ( PE ) file is double-clicked, cross probing between the UM ( PE ) and the layout is executed. The LVS error part is highlighted in the layout, so it is easy to find the LVS error.

2. Execution of Guardian LVS with the LVS project file (*.gpr)

1) Load the Guardian LVS project file *.gpr by clicking the Load button at the bottom of the Project Settings dialog.

2) If you would like to compare another netlist, change the setting.

3) Run LVS.

4) The LVS result is displayed in the LVS Log file.

3. Execution of Guardian LVS with examples

Case1: netlists are EQUIVALENT (see lvs_run_case1.png )
1) Load lvs_run_case1.gpr .
2) Run LVS.

Case2: netlists are NOT EQUIVALENT (see lvs_run_case2.png )
1) Load lvs_run_case2.gpr .
2) Run LVS.

Case3: netlists are topologically EQUIVALENT, parameter errors are detected (see lvs_run_case3.png )
1) Load lvs_run_case3.gpr .
2) Run LVS.

Case4: netlists are topologically EQUIVALENT, label mismatch is detected (see lvs_run_case4.png )
1) Load lvs_run_case4.gpr .
2) Run LVS.