Mentor Graphics IC Graph Tutorial

Important:

Layout drawing is time consuming. You will save time if you have the stick diagram of your schematic in advance.

Tien-Cheng Bau, Savitha Gandikota, and Jung Suk Yun

Samiha Mourad

Electrical Engineering Department

Date of last revision: 09/14/00

Index:

To perform verification on layout, please refer to ICverify tutorial

1. Introduction

In this tutorial, we are going to layout a CMOS inverter the schematic of which is shown in Fig 1-1. The final layout will look like the figure shown in Fig 1-2.

Figure 1-1. Transistor level schematic of an inverter

Figure 1-2. Layout of an inverter cell

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2. Preparation

We recommend that you read the 'Design Rules' (page 1-1 to page 1-15) in the IC Graph Menu (PostScript file).

Note:The shapes that you will be using in the layout must conform to the rules derived for the technology which your design is meant for.

PLEASE, DO NOT PRINT OUT THESE FILES !!!!!

The rules are listed in a system text file "$CMOSN_LIB/physical_lib/cmosn.rules".

Before using Mentor Graphics and IC Graph:

Add the following lines in your .profile

. /usr/local/scripts/setup.mentor-B.2.sh

SYNLIB=/LINKS/mentor/parts/cmosn_lib/autologic

MGC_PLOT_DEFAULT_PRINTER=laser

export MGC_PLOT_DEFAULT_PRINTER

Remember to execute

$ . .profile

If using C-shell add the following lines in your .cshrc:

./usr/local/scripts/setup.mentor-B.2.csh

setenv SYNLIB /LINKS/mentor/parts/cmosn_lib/autologic

setenv MGC_PLOT_DEFAULT_PRINTER laser

Remember to execute

$ source .cshrc

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3. Starting Ic Graph

Invoke 'IC Graph' by

`$ dmgr`

Double click 'ic' icon in the 'Tools' window as shown in Fig 3-1 to invoke 'IC Graph'

Note:Don't forget to maximize 'IC Graph' window by clicking on the upper-right button on the window frame when it appears or part of the palette will be hidden.

Figure 3-1. Double click 'ic' icon to invoke Ic Graph

Select 'Create' on the right hand side session palette in the IC Graph window, a dialog box will appear as shown in Fig. 3-2

Figure 3-2. Create Cell dialog box

Note:

For editing an existing layout, select 'Open' instead of 'Create'.

Enter the name of the device you will layout in the "Cell Name" box. This can be any name you like, it need not be the schematic name. In this example, enter 'inv' .(see Fig 3-2)

Enter "$CMOSN_LIB/physical_lib/cmosn" into both the "Process" and "Attach Library" fields.

Note:For an existing cell, you may use the 'Navigator...' to locate the cell in your directories.

Click on 'OK'. A new layout sheet window will appear.

Mentor Graphics IC Graph Tutorial

Important:

Tien-Cheng Bau, Savitha Gandikota, and Jung Suk Yun

Samiha Mourad

Electrical Engineering Department

1. Introduction

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2. Preparation

PLEASE, DO NOT PRINT OUT THESE FILES !!!!!

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3. Starting Ic Graph

$ dmgr

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`$ dmgr`