Digital VLSI Chip Design
with Cadence and Synopsys
CAD Tools


By Erik Brunvand


Please note that all this information is provided "as is" and without any warranty of any kind. Please use the information at your own risk. This warning is especially true of the cell libraries!

This is a library that contains pad cells for the ON (formerly AMI) C5N 0.5 micron CMOS process. These are pads that originally came from Tanner Research , distributed through MOSIS. They have been modified at the University of Utah to make them DRC and LVS complient. Using these pads you can DRC and LVS and simulate your entire chip including the pad rings. See Section 12.2 for details about these pad cells.

Note that there is an inconsistency in the MOSIS SCN3M_SUBM design rules that relates the pad size and spacing. MOSIS knows about this, and although they aren't changing the SCMOS v8 design rules, they say that the pad rings built from these pads are known to work. There is a square of "nodrc" material on the actual pad portion of the cells so that you don't see the errors when running DRC. However, if, as I suggest is a good idea in the book, you export your final GDSII, then read that back in to a new library for a final DRC/LVS check against your schematic, you will see those errors on the pad spacing. You can apparently ignore those errors (we've never had any problems, but remember, all these libraries are to be used at your own risk with no warranties!)

The UofU_Pads library now comes in two flavors: CDB for Cadence IC v5, and OA dfor Cadence IC v6.

To use the library, simply untar the UofU_Pads directory from the gzipped tar file. Then point to the location where you put the UofU_Pads library directory in your cds.lib file. You can put this in the NCSU CDK cds.lib file in $CDK_DIR/cdssetup/cds.lib, or in the $LOCAL_CADSETUP/cadence/cds.lib file, or in the cds.lib file that is in the directory from which you start the Cadence tools. The format in the cds.lib file is:

DEFINE UofU_Pads <path-to-the-directory>/UofU_Pads

Note that this cell library uses the UofU_TechLib_ami06 technlogy, and the devices in the schematic views use the transistors from the NCSU_Analog_Parts library from the NCSU CDK.

Last modified May 18, 2011.