《教学en_cadence+spectre+使用手册》由会员分享，可在线阅读，更多相关《教学en_cadence+spectre+使用手册（21页珍藏版）》请在金锄头文库上搜索。
1、CS/EE 5720/6720 Analog IC Design Tutorial for Schematic Design and Analysis using Spectre Introduction to Cadence EDA: The Cadence toolset is a complete microchip EDA (Electronic Design Automation) system, which is intended to develop professional, full-scale, mixed-signal microchips. The modules in
2、cluded in the toolset are for schematic entry, design simulation, data analysis, physical layout, and final verification. The Cadence tools at our university are the same as those at most every professional mixed-signal microelectronics company in the United States. The strength of the Cadence tools
3、 is in its analog design/simulation/layout and mixed-signal verification and is often used in tandem with other tools for digital design/simulation/layout, where complete top-level verification is done in the Cadence tools. An important concept is that the Cadence tools only provide a framework for
4、doing design. Without a foundry-provided design kit, no design can be done. The design rules used by Cadence set up in this class is based for AMIs C5N process (0.5 micron 3 metal 2 poly process). So, how is Cadence set up? Broadly, there are three sets of files that need to be in place in order to
5、use Cadence. 1) The Cadence tools These are the design tools provided by the Cadence company. These tools are located in the /home/cadence directory. They are capable of VLSI integration, project management, circuit simulation, design rule verification, and many other things (most of which we wont u
6、se). 2) The foundry-based design kit As mentioned before, the Cadence tools have to be supported by a foundry-based design kit. In this class, we use Cadence design kit developed by the North Carolina State University (NCSU CDK). NCSU CDK provides an environment that has been customized with several
7、 technology files and a fair amount of custom SKILL code. These files contain information useful for analog/full- custom digital CMOS IC design via the MOSIS IC fabrication service (http:/www.mosis.org). This information includes layer definitions (e.g. colors, patterns, etc.), parasitic capacitance
8、s, layout cells, SPICE simulation parameters, Diva rules for Design Rule Check (DRC), extraction, and Layout Versus Schematic (LVS) verification, with various GUI enhancements. For more information on the capability of the NCSU CDK, go to http:/www.cadence.ncsu.edu/CDKoverview.html 1 This design kit
9、 is located in the /home/cadence/ncsu/local directory. All the design parameters that are needed by the Cadence tools are located in various files in the sub-directories you will find here. The nominal spice parameters for n type transistors for AMIs 0.5 micron process used in this class can be foun
10、d in /home/cadence/ncsu/local/models/spectre/nom/ami06N.m. 3) The set up files in your local cadence directory There are set up files that should be in your local Cadence directory (i.e. the directory from which you invoke Cadence) that sets up the required local environmental variables for Cadence
11、to work on your computer terminal. They are as follows: .cdsinit, .cdsplotinit, .simrc (sets up the variables to be used by NCSU CDK) .cdsenv (not essential, but sets your preferences which can be different from user to user) Also we need a .cshrc file to source the current version of cadence we are
12、 using in this class. Now, of the three sets of files, the first two sets containing the cadence tools and the NCSU CDK have been already set up by the Cadence Administrators for the class. In this tutorial, the process of setting up the required files in your local cadence directory is explained. S
13、etting up Cadence2000 Note: People who have already set up Cadence before still need to follow the steps below. Before you start using cadence you need to complete the following steps: 1. First, before anything else, make a directory from which to run Cadence. This is important so that all of Cadenc
14、es files end up in a consistent location. I recommend making an IC_CAD directory and then under that making a cadence directory: cd mkdir IC_CAD mkdir IC_CAD/cadence 2. You need to add the following lines in your .tcshrc file (or whatever shell setup file you use) Just open it up with emacs and add:
15、 set path = (/uusoc/facility/cad_common/local/bin $path) setenv ICDIR IC_CAD setenv CADENCEDIR $ICDIR/cadence 2 setenv LOCAL_CADSETUP /uusoc/facility/cad_common/local/class/5830/cadence Adding the first line will update your search path to include the path of the customized CAD tool startup scripts.
16、 The next lines set your working directory for cadence as IC_CAD/cadence. The fourth line sets up the path to a directory that contains class-specific settings. After you save this file you can log out and log in again, or you can source it from the command prompt in the following way. : source .tcshrc The sourcing only needs to be done the first time. After that the .tcshrc file will be sourced automatically when you log in and start up a shell. 3 Starting Cadence 2000 an
