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Model files

MOS models

These are sample models obtained from public domain data such as parametric run results published on MOSIS's website or predictive technology models from These are provided so that students can get a feel for performance of circuits in various technologies. Do not use these to simulate circuits that are to be fabricated-get the models for your process from the fabrication foundry. Click on the process name for more information

For realistic modeling of circuits, include the drain and source junction capacitances by specifying appropriate values of "ad", "as", "pd", "ps" for all MOS transistors. In absence of layout information, you can use 2Lmin to be junction length(i.e. 0.36µm in a 0.18µm technology) and set ad = as = 2WLmin and pd = ps = 2(W+2Lmin).

Add the following line to your netlist to use these models with Eldo
.option compat

Opamp models

Use these models only with +/-5V supply. Because of the way theyy are modeled, the gain, and more crucially, the unity gain frequency is very sensitive to the supply voltage. At +/-6V, the dc gain and unity gain frequency are more than 3x higher than at +/-5V.

System level simulators

Drawing tools

Xcircuit is an excellent tool for drawing publication quality circuits. You can use it for your reports. It can also be used for schematic capture and netlisting, but is a bit cumbersome. Download the latest version of Xcircuit at here. You might want to go through the schematic capture tutorial in order get familiar with the netlisting process. If you use machines in FPGA/VLSI/IE labs, check to see if Xcircuit is already installed.

Circuit Simulators in our labs

Cadence is a front to back IC design environment and is installed in our research labs. If you are working on a project in these labs, you can also use the simulator for coursework. To use the MOS models below, use the MOS symbols from analogLib with the right model names(cmosp and cmosn for pMOS and nMOS respectively). ahdlLib has a lot of macromodels.

Design Architect and Eldo from Mentor Graphics can be used for schematic capture and circuit simulation respectively. They are installed at the locations below:

You need to setup the following environment variables

The executables are dmgr_ic(full project manager), da_ic(schematic editor), and eldo(circuit simulator) respectively. ezwave is the waveform viewer. Here is a template mgc_location_map which includes the standard libraries and the UMC180 library for use with da_ic and eldo.

Freeware circuit simulators

Any simulator that is capable of using the models below can be used for your simulations. Free tools that have schematic capture and simulation capabilities include the following. You may have to make some trivial modifications to the syntax of model files for these simulators.

In addition to these a number of open source circuit design tools(not just circuit simulators) are listed at this link.