1) The document outlines the steps for setting up the Cadence design environment and using Cadence tools for VLSI simulation and layout, including creating a library and cells, schematic capture, simulation, and layout. 2) Key steps covered include making a new library and cells, inserting symbols and setting properties, adding I/O ports, saving schematics, hierarchical editing, simulation setup and running DC and AC analyses, and layout steps like inserting layout components and design rule checking. 3) The document provides a tutorial on using Cadence for both analog circuit simulation and layout design for a VLSI computer engineering course.

1. University of California, Santa Barbara
ECE 194BB/594BB fall10 VLSI for Computer Engineering
Cadence Simulation and Layout Tutorial
Chin-hsuan ( Jennifer) Chen Prof. Luke Theogarajan
Before we start, please attach the following code in your .cshrc file:
#594
set CDK_DIR = "/eci/tech/ECE594A/ncsu-cdk-1.5.1"
source $CDK_DIR/cdssetup/setup.csh
OUTLINE
• Environmental setup
• Cadence Simulation
• Cadence Layout
Environmental Setup
• ECI account - using tcsh
• edit .cshrc file
• source .cshrc
• create your own directory (ECE594BB)
• invoking icfb& in the directory - you will see a CDS.log and Library Manger
Making Library - We will be using 0.18um technology in this class
• From Library manager, select File -> New -> Library
• A new window called Create Library pops up
• Enter the library name LAB in the Name field
• Choose the option of attach to existing tech library, and choose TSMC 0.20u CMOS018
(6M, HV FET, sblock). Press OK
•

2. University of California, Santa Barbara
ECE 194BB/594BB fall10 VLSI for Computer Engineering
Making Cells
• Select LAB
• From Library manager, select File -> New -> Cell View...
• A new window called Create New File pops up
• Enter INV1 for Cell Name. Press OK
• You could see from the Library Manger that Cell INV1 is created, with schematic in the view
section in library LAB.
• Another window pops up: Schematic Editing: LAB INV1 schematic
•

3. University of California, Santa Barbara
ECE 194BB/594BB fall10 VLSI for Computer Engineering
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•
Inserting Symbols
• Press key “i” or the instance button from the toolbar
• Press “Browse” from the popped window (Add Instance)
• Pick the desired cell from library manager
NCSU_Analog_Parts → N_Transistors →nmos
• Close the Component Browser
Editing Properties of Symbol
• After closing the Component Browser, the corresponding library and cell name appears in the
popped window
• Fill some properties for the symbol
• Name: Mn
• Model Name: tsmc20N
• Multiplier: 1
• Width: 1u
• Length:1u
• Press Hide Button
•

4. University of California, Santa Barbara
ECE 194BB/594BB fall10 VLSI for Computer Engineering
Adding and Connecting
• Insert nmos, pmos, vdd, gnd (in Supply_Nets) symbols
from the NCSU_Analog_Parts library
• nmos: 1u/1u/1
• pmos: 3u/1u/1
• vdd: DC voltage=3.3V
• gnd
• Press key “w” to place wire, “esc” to exit
Adding Net Names
• Press key “l” (Label) and key in the corresponding node name in the popped window
• Press Hide and drag the “net name” to some wire/node
Indicating I/O Ports
• Press key “p” or the pin button from the toolbar
• Specify the Pin Name and choose (input/output/inout)
• If pin connect to some net, the pin name should be identical to net name to avoid confusion.

5. University of California, Santa Barbara
ECE 194BB/594BB fall10 VLSI for Computer Engineering
• Press Hide and drag the pin to the right place
Saving the Schematic
• Press key “X” or check and save button from the toolbar
• To save the schematic and make sure schematic is error free
• The main window reports the status of schematic
Open Existing Cell
• From main window, choose File → Open
• In the popped window, choose the Library and Cell Name you want
• Choose the desired View Name, and Press OK
Creating Symbol
• Open INV1 schematic first
• From schematic editing window, Design → Create Cellview → From Cellview…
• Make sure that Library and Cell Name are correct.
• Choose Composer-Symbol and Press OK

6. University of California, Santa Barbara
ECE 194BB/594BB fall10 VLSI for Computer Engineering
Symbol Editing Window
• Symbol Editing Window pops up
• You can edit the position of Pins and the shape of the symbol
An Inverter Example
• Making a new schematic named INV1_SIM from the same library

7. University of California, Santa Barbara
ECE 194BB/594BB fall10 VLSI for Computer Engineering
Inserting Custom Symbols
• Follow the steps of Inserting Symbols
• Inserting Cell INV1 from Library Lab
• Press Close and Hide
•
Inverter Schematic
• Place the INV1 symbol on the Schematic Editing Window, output pin, input source and VDD
• vdc: DC voltage=1.65V

8. University of California, Santa Barbara
ECE 194BB/594BB fall10 VLSI for Computer Engineering
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Hierarchical Editing
• In Schematic Editing Window, Design → Hierarchy →Descend Edit…
• Pop up window: Descend, press Hide
• Pick the symbol you want to edit
• Choose Schematic View and press OK
Hierarchical Editing
• After Choosing Schematic View, the Schematic Editing Window descends to view of INV1
schematic
• Any symbol in this schematic can be modified arbitrarily
• Remember to save changes

9. University of California, Santa Barbara
ECE 194BB/594BB fall10 VLSI for Computer Engineering
Ascend Editing
• In Schematic Editing Window, Design → Hierarchy →Return to ascend one level Or
Design → Hierarchy → Return To Top to ascend back to top level (“b”)
Invoking Analog Environment
• From Schematic Editing Window, Tools → Analog environment
• A new window called Analog Design Environment (ADE) pops up
Indicating Simulator
• From ADE window, Setup →Simulator/Directory/Host…
• Choose hspiceS as simulator, and click OK.
•
DC Analysis
• From ADE window, Analyses → Choose …
• Choose dc analysis
• From 0 To 3.3 By 0.1 (Volts)
• Source Name: /vin (choose Select Source and select the input voltage source from the
schematic editing window)

10. University of California, Santa Barbara
ECE 194BB/594BB fall10 VLSI for Computer Engineering
• Press OK
•
•
Output Setup
• Outputs →To Be Plotted → Select On Schematic
•
• Select the out wire, the wire will be high light in different color.
• ADE window will show the output signal to be plotted on the down right column.

11. University of California, Santa Barbara
ECE 194BB/594BB fall10 VLSI for Computer Engineering
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• DC Analysis
• From ADE window, Simulation → Run…
•

12. University of California, Santa Barbara
ECE 194BB/594BB fall10 VLSI for Computer Engineering
AC Response
• Making a new schematic named INV1_SIM_AC from the same library
• Since now we want to sweep frequency on the input node, add a voltage source (in
NCSU_Analog_Parts → Voltage_Sources →vdc ) on it.
• DC voltage=1.56V
• AC magnitude=1V
Invoking Analog Environment
• From Schematic Editing Window, Tools → Analog environment

13. University of California, Santa Barbara
ECE 194BB/594BB fall10 VLSI for Computer Engineering
• A new window called Analog Design Environment (ADE) pops up
AC Analysis
• From ADE window, Analyses → Choose …
• Analysis: ac
• Start from 1Hz, end to 10GHz
• Sweep type: logarithmic
• Point per Decade: 10
• Run simulation
AC analysis result
• From ADE window, Results → Direct Plot → AC Magnitude & Phase
• Back to the cellview, select the nodes (out)
• Then, press ESC to get the figure

14. University of California, Santa Barbara
ECE 194BB/594BB fall10 VLSI for Computer Engineering
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Layout Turtorial: We are using a different example!
• From Library manager, select File -> New -> Cellview...
• Library Name: LAB
• Cell Name: test_layout
• View Name: layout Tool: Virtuoso

15. University of California, Santa Barbara
ECE 194BB/594BB fall10 VLSI for Computer Engineering

16. University of California, Santa Barbara
ECE 194BB/594BB fall10 VLSI for Computer Engineering
Environmental Setting:
Change the display:
Options→ Display...
select Pin Names, and change the display levels start from 0 to 20
Inserting Layout component
• Press key “i” or the instance button from the toolbar
• Press “Browse” from the popped window
• Pick the desired cell from library manager
NCSU_TechLib_tsmc02 → nmos →layout

17. University of California, Santa Barbara
ECE 194BB/594BB fall10 VLSI for Computer Engineering
• In the Create Instance window:
• Multiplier: 1
• Width: 1u
• Length:1u
• press Hide
•
For PMOS 3um/1um,
• Multiplier: 1
• Width: 3u
• Length:1u
• press Hide

18. University of California, Santa Barbara
ECE 194BB/594BB fall10 VLSI for Computer Engineering
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connect the poly gate and the drain of pmos and nmos together
r: rectangular - choose the layer you would like to make connection
o: contact - connection from layer to layer
s: stretch - stretch the size of the rectangular
you can find more option from: edit->...
Please check the design rules to see the minimum spacing between layers and other
consideration.
Remember to add body contact!
Design rule check (DRC)
Verify->DRC

19. University of California, Santa Barbara
ECE 194BB/594BB fall10 VLSI for Computer Engineering
After doing the design rule check, and the design is design rule error free...
We will extract the circuit from your layout
Verify->Extract
LVS: Layout versus Schematics
create Schematics

20. University of California, Santa Barbara
ECE 194BB/594BB fall10 VLSI for Computer Engineering
Verify->LVS...
press run
After the analysis job succeed, go to Artist LVS->info, there will be a display run information,
click on Log file to see whether the net-lists match or not and the detail analysis.