pads standard plus evaluation guide

PADS Standard Plus Evaluation Guide

Included in this Guide:

A guided tour of PADS including: Introduction to PADS Standard Plus Schematic Capture Pre-Layout Analysis Library Management Constraint Management Placement and Routing Routing with PADS Router Post-Layout Analysis Archive Management

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Introduction to the PADS Standard Plus Introduction ....................................................................................................... Intro - 1 Design Process Overview ................................................................................... Intro - 2 PADS Standard Plus Highlights ........................................................................... Intro - 3 About This Evaluation ........................................................................................ Intro - 5 Schematic Capture Lesson 1: PADS Schematic Workspace ................................................................... L1 - 1 Lesson 2: Creating a New Schematic ..................................................................... L2 - 1 Lesson 3: Component Management ..................................................................... L3 - 1 Lesson 4: Wiring Schematic Parts .......................................................................... L4 - 1

Pre-Layout Analysis Lesson 5: Signal Integrity Analysis Using LineSim .................................................. L5 - 1

Library Management Lesson 6: Working with Central Library Manager .................................................. L6 - 1

Constraint Management Lesson 7: Constraint Creation ................................................................................ L7 - 1

Contents

Contents i

Placement and Routing.................................................................................... Lesson 8: Placing Parts .......................................................................................... L8 - 1 Lesson 9: Interactive Routing ................................................................................ L9 - 1

Routing with PADS Router Lesson 10: Manual Routing of High-Speed Nets.................................................. L10 - 1 Lesson 11: Autorouting ........................................................................................ L11 -1

Post Layout Analysis Lesson 12: Signal Integrity Analysis ..................................................................... L12 - 1 Lesson 13: Thermal Analysis ................................................................................ L13 - 1

Archive Management ...................................................................................... Lesson 14: Archive Management ........................................................................ L14 - 1

Conclusion .......................................................................................................

Appendix 1: ODBC Setup ................................................................................

Contentsii

Introduction to PADS Standard Plus

Introduction

Introduction Design Process Overview PADS Standard Plus Feature Highlights About this Evaluation

Welcome to the PADS Standard Plus Evaluation. Our goal is to introduce you to the broad spectrum of highly-integrated PADS design tools and assist you in understanding how to apply them to your most complex design situations.

We invite you to use this guide to fully explore both the power and ease of use of PADS.

This Evaluation Guide will introduce you to the major features and capabilities of PADS to help you understand how to simplify your design process to meet the demands of today's world. We will review key aspects of the workflow from symbol creation to design capture, to layout, placement of components, routing, rules and constraints entry, interactive routing, autorouting, and other areas. The focus throughout this guide is to provide tips on how to get your job done more efficiently and use PADS effectively to accomplish the full spectrum of design tasks of tomorrow's designs today.

Introduction

A Complete SolutionA complete design solution that uses advanced technologies to deliver a feature rich, truly integrated solution that features a tightly-integrated workflow, world-class support, and a comprehensive collection of training resources to help you work more efficiently. In short, PADS offers time-saving integration, simplified workflows, and an unprecedented value.

Further ExplorationFinally, remember that this document is an evaluation guide, not a comprehensive user guide. Your most complete source of detailed feature information is the Help.

Working TogetherWe work with real-world design examples and also introduce you to many of the great new features highlighting some of the more interesting techniques with steps and lots of illustrations.

Every effort has been made to ensure your experience will be satisfying, but at times we do make mistakes. In the event that you have any difficulty in using this guide or encounter any need for assistance, Mentor Graphics is ready to help through the PADS Community network and SupportNet. Please explore the wide world of PADS at the following icons:

Introduction Intro 1


Design Process OverviewTaking a new design from concept to completion requires a designer to pay attention to many details. We all know that designing a printed circuit board is a continuous process of making design decisions and tradeoffs. Throughout the design process, you must weigh a number of conflicting factors and make calculated design choices in order to obtain the best possible design outputs.

Knowing that your design tools have the ability to provide and manage the required content gives you a strong foundation on which to build your design. PADS Standard Plus offers an intelligent and predictable fully featured front-to-back design flow to create quality designs which maintain your constraints.

Schematic Capture with Pre-Layout Analysis

PCB Design Layout with Post-Layout Analysis

Create a Design Project

Documentation and Manufacturing Outputs

Archive Management

The Design Process

Steps In the Design Process

Though there are hundreds of operations you must perform to produce a final design, we can distill the process down to a few basic steps:

1. Creating a Design Project

2. Performing Schematic Capture

Creating the Top Level Schematic Adding Components to the Schematic Connecting the Components Verifying the Design Performing Design Analysis (pre-layout) Defining Constraints Forward Annotating the Logical Design for Physical Design

3. Performing Layout Design

Configuring for Physical Design Adding Physical Constraints Placing Parts Routing Critical Nets Auto Routing Nets Generating Plane Structures Checking Design Rules (DRC) Post Layout Verification

4. Creating Documentation and Manufacturing Outputs

Creating Schematic Release Documentation Creating Manufacturing Outputs Performing Engineering Change Orders (ECO)

5. Archive Management

Partitioning your workflow to align with these steps will help you establish a structured approach to organizing your design tasks. It will also provide you with a number of checkpoints for reviewing your design data.

IntroductionIntro 2

PADS Standard Plus HighlightsMentor Graphics, the worlds number one provider of PCB design solutions, has combined the expansive capabilities of the PADS product line into a series of affordable PADS offerings. PADS Standard Plus provides just the right mix of technology necessary for complex PCB design, supplemented with a variety of add-on capabilities should your needs change.

PADS Standard Plus offers a complete integrated solution that improves personal productivity and speeds your time to market. Available in configurations of increasing functionality, the PADS Standard and PADS Standard Plus solutions provide low-risk entry points to the PADS flow.

A PADS Solution for EveryonePADS Standard and PADS Standard Plus are designed to meet the specialized needs and job requirements of individual engineers and PCB designers:

PADS Standard is designed for the Layout Designer who wants to quickly define and complete PCB designs.

PADS Standard Plus is created for Engineers who want complete product definition within a single solution and Layout Designers who need high-speed routing capabilities.

The PADS Evaluation Guide will let you explore and experience the incredible power and integration available to accelerate your product development cycle.

Design DefinitionThe PADS flow delivers the most robust system design capture and definition functionality available, including intuitive project and design navigation, unlimited hierarchical support, design reuse, advanced design attribute and constraints management, annotation including design constraints, cross-probing with layout and routing, direct schematic-to-signal-integrity analysis link and Archive Management. Component management is also available.



Analog AnalysisIntegration with HyperLynx, provides a board-level simulation analysis and verification environment that is integrated into the PADS schematic design environment. Using a single schematic to drive both the simulation and PCB applications, PADS effectively eliminates costly and error-prone schematic re-entry, therefore significantly shortening the overall development cycle.

Signal Integrity AnalysisSignal integrity (SI) analysis (powered by HyperLynx) is an essential part of modern electronic design. Increasingly fast edge rates in todays integrated circuits (ICs) cause detrimental high-speed effects, even in PCB designs running at low operating frequencies. As driver ICs switch faster, a growing number of boards suffer from issues such as crosstalk, over/undershoot, ringing, glitching, and timing problems. PADS design solutions offer powerful and easy-to-use signal integrity capabilities on the engineers desktop. With pre-layout analysis capabilities for defining routing constraints, to verification of the routed board to ensure your design goals are met, PADS design solutions offer a complete environment for all your signal integrity analysis needs.

Thermal AnalysisEngineers and PCB designers can analyze board-level thermal problems on placed, partially routed, or fully routed PCB designs. Temperature profiles, gradients, and excess temperature maps enable designers to resolve board and component overheating early in the design process.

PCB LayoutAs the standard in desktop PCB layout tools, PADS offers unparalleled price-performance for the layout and design of complex circuit boards, including high-speed applications and RF circuits. PADS offers advanced design rules with real-time design rule checking, bi-directional crossprobing, RF design functionality, split-plane generation, auto-dimensioning, direct DXF import into both the board and part library editors, physical design reuse, advanced fabrication verification tools, and 3D viewing. Also available are assembly variant functions, test coverage auditing, chip-on-board / advanced packaging, and an interface to third party CAD/CAM tools.

Interactive & Automatic RoutingMany designers of high-speed and/or dense designs require exacting manual control of critical signal traces, but could also benefit from the speed and built-in intelligence of an autorouter. The router provides both advanced interactive and sophisticated autorouting for all applications. Whether interactively routing with orthogonal, diagonal, or any-angle styles, or differential pair routing with unique rule assignment or trace length requirements, the router provides exacting control.

Intuitive graphical monitoring tools provide real-time feedback for correct-by-design methodology. Proven routing algorithms enable robust design rules and advanced design constraints to be applied between objects or groups of objects such as components, layers, nets, and vias.

The advanced autorouter simplifies routing operations most suited for an autorouter, including fanout and routing, by individual components or groups of components.

IntroductionIntro 4

Mouse Usage and TermsThroughout the guide, you will see terminology for RMB, MMB and LMB direction. These terms refer to Mouse button usage as shown below:

LMB refers to use of the left mouse button for selection and deselection of objects under the cursor.

MMB refers to use of the middle mouse button or scroll wheel for Panning and Zoom In and Out.

RMB refers to use of the right mouse button for context sensitive popup menus.

Note: View Help for more information about Function Keys and Mouse Mappings.

About This Evaluation This Evaluation Guide and accompanying lesson files will allow someone with limited experience with the PADS workflow, the opportunity to review several of its new features and capabili-ties. Keep in mind this presentation is a snapshot of the full range of features PADS provides.

The Evaluation environment delivers the files you will need to work with to the C:\PADS_Stnd_Plus_Eval\PADSVX.1 directory. This is necessary since the software has specific parameters that are setup within the lesson files enclosed.

The content of the evaluation material should include this PDF file of the Evaluation Guide, and

* Schematic, Simulation and PCB Lesson files (located in the C:\PADS_Stnd_Plus_Eval\PADSVX.1 directory), * Datasheets (located in the C:\PADS_Stnd_Plus_Eval\PADSVX.1\Datasheet directory) and * Libraries and other supporting files (in the C:\PADS_Stnd_Plus_Eval\PADSVX.1\Libs directory).This evaluation experience is intended to be used with the PADS software. The evaluation has Lessons dedicated to interfacing with PADS software. Customers with a desire to run through an Xpedition flow should request a different evaluation from their local Mentor Sales and Technical representatives.


Evaluation Environment SetupIf youre running evaluation software on your local system, we encourage you to perform a couple of configuration steps prior to executing these evaluation lessons in order to synchronize your system response with the snapshots presented in the evaluation guide.

Copy the two files (DxDesigner.xml and DxDesigner.wsp) from the C:\PADS_Stnd_Plus_Eval\PADSVX.1\Libs folder to the WDIR folder. The location of the WDIR folder is specified during the PADS VX installation (typically, it is the C:\PADS Projects) and is stored in the WDIR_PADSVX_1 environment variable on your computer. This synchronizes xDX Designer environment (color scheme, Navigator settings, toolbar visibility, etc.) with the steps and snapshots inside the Evaluation Guide lessons.

Copy the ces.ini file from the C:\PADS_Stnd_Plus_Eval\PADSVX.1\Libs folder to the C:\Users\\AppData\Local\MentorGraphics\PADSVX.1 folder, where stands for the login name of the user who is performing the evaluation. This synchronizes the Constraint Manager environment with the Evaluation Guide.

Typically, you need to perform these steps once, however executing evaluation lessons changes the environment and if youre rerunning some exercise you may want to execute these steps at the beginning of each exercise.

IntroductionIntro 6

Schematic Capture

In This Section:

PADS Schematic Design Environment and Workspace

Creating a New Schematic Component Management Wiring the Schematic

Lesson 1: PADS Schematic Design Environ-ment and WorkspaceYour PADS Schematic Design environment starts when you select from the Start menu, Start > All Programs > PADS VX.1 (32bit) > Design Entry > xDX Designer.The PADS Schematic Design Start Page contains links to tutorial information, videos, online help features, and more. These items can help you become productive quickly. If you do not wish to see the Start Page, you can toggle it off by selecting View > Start Page.The PADS Schematic Design environment follows Windows navigation standards. It supports pulldown menus, hot keys,

PADS Schematic Design Environment and Workspace L1-1

Schematic Capture

toolbars and tooltips.

The software is object aware so the Right Mouse Button menu selections will change automatically based on the object selected.

Review the next pages to become familiar with the PADS Schematic Design environment User Interface and toolbars.

NOTE: We recommend that you perform the environment setup steps described in the Introduction section. This ensures that your PADS Schematic Design environment is in sync with the screen shots inside the Evaluation Guide.

Start PADS Schematic Design Environment

Start xDX Designer from the Start menu to open xDX Designer to the Start Page.

Introduction to the User Interface (Main Window)

Menus Toolbars Workspace Properties

Symbol Viewer

Navigator Pane

Status BarPADS Data Management

Search Window (xDX Databook)

PADS Schematic Design Environment and WorkspaceL1-2

Open the Lesson 1 Database

Click Open on the Start Page and browse to and select C:\PADS_Stnd_Plus_Eval\PADSVX.1\Lesson1\Lesson1.prj. Become familiar with the Main User Interface shown here.

Extended TooltipsAll of the toolbar icons contain tooltips to help you understand the commands you select. The PADS Schematic Design environment also contains extended tooltip animation for most of the commands on the toolbars. These animations provide you with a brief video to minimize the learning curve and place immediate help at your fingertips. Quick-key commands are also provided within the tooltips.

Schematic Capture


Practice Viewing Extended Tooltips

Hover over any toolbar icon to see the normal tooltip along with the Quick-key command. Hover over the icon again, but leave your cursor over the icon for brief time (about 3 seconds). The animation for the command begins playing and shows additional information and usage for the command.

Toolbars

The Main Toolbar

New Cut

Print Copy File Viewer

Undo

Paste

Verify

Find/Replace Redo Package LayoutSynchronize

PCB

Constraint Manager

PCB Interface

xDM Librarian (Library Manager)

Export Remote Development Database

Import Remote

Development Database

xDX I/O

Designer

GRC Run Graphical Rule Checker

The View Toolbar

Route Mode

xDX Databook

Properties

Selection Filter

Zoom Out

Restore Zoom

Zoom In

Zoom Area

Fit Selected

Navigator

OutputFit All Push

xDX PCB

Viewer

My Parts

Save Zoom

Add Properties

Mode

ICT Viewer

Push ICT

Pop

PADS Decal Preview

Enable/Disable Selection Filter

Review the Main and View Toolbars

Hover over the Main and View toolbars to see the tooltips and/or videos associated with each tool.


Addins Toolbar

Toolbars (Continued)

The Add Toolbar

The Transform Toolbar

BusSelect Box Line

Multi-Net Connection

Special Components

Block Circle Text Arc

Mirror StretchRotate

90Align

MiddleSnap to

GridAlign Top

Align Bottom

Grid On/Off

Align Left

Flip ScaleDisconnect

Cut

Nets

Delete

Grid Spacing

The Grid Toolbar

Align Center

Align Right

Bring Forward

Send Backward

Bring to Front

Send to Back

Manage Sheet

Backups

Distribute Horizontally

Distribute Vertically

Grid Units

Backup Sheet

Review the Add, Grid and Transform Toolbars

Hover over the Add, Grid and Transform toolbars to see the tooltips and videos associated with these toolbars.

Schematic Capture


Add Missing

Ports

ArrayNet

Show Alignment Markers

Reassign Names

Navigator Tree PaneThe Navigator presents you with a central viewport into your design. All components, nets and other design elements are available for browsing and querying from this common window.

The Navigator Tree pane, as with all of PADS Schematic panes, is dockable and can be moved anywhere you wish on the screen. We will now practice using the Navigator Pane to view all of the design elements and to jump to various sheets or nets quickly and easily.

The Navigator Tree Pane

Open the Navigator Tree by selecting the icon on the Main toolbar if it is not already open.

Double click the name CORPORATE and notice the main window displays the sheet CORPORATE.1 (the sheet name is also shown on the tab at the top of the design window).

Next select the [+] icon located to the left of the CORPORATE schematic name.

Note: The tree should be expanded to look similar to this example.


The Navigator Tree Pane (continued)

Double-click Sheet 4 and watch the main workspace area update to show sheet 4.

Note: Notice the schematic sheet tabs located at the top display both Corporate.1 and Corporate.4.

Notice there are 2 categories that appear in the Navigator for the sheet. (Symbols and Nets).

Select the [+] item to expand the Symbols section.

Click any symbol listed and notice the software automatically selects the item in the workspace window. This concept is called crossprobing. When you double-click an object it will move the schematic page to the correct location with the object highlighted.

Note: You may need to zoom out to see items selected during crossprobing in the workspace area (by double-clicking the object in the navigator).

Schematic Capture


Object TooltipsThe PADS Schematic Design environment supports tooltips for Symbols (Components) and Nets. The visible attributes are configurable. Lets take a closer look.

Open Project Settings by selecting Setup > Settings. Click Display and notice the options for controlling

various display settings including Show Tooltips. Enable Components and Nets.

Click OK. Click Selection Filter on the View toolbar and enable

All. Place your cursor over any component to see the tooltip.

Place your cursor over any net to view the netname tooltip.

Note: This is a very convenient way to get information without having to zoom in and out to view and identify an object on the schematic.


Help System

Click Help to access documentation, support, SupportNet and tips. Take a moment to view the resources available from this menu.

View all available shortcuts and system strokes by selecting Help > Show Bindings and Help > Show Strokes.Note: Navigational controls can also be configured in Setup > Settings > Schematic Editor > Strokes, Pan and Zoom. You perform strokes by holding down the Right Mouse Button and drawing the stroke.

Navigation (Pan and Zoom)

Zooming

Click on any open area in the workspace.

Press the F7 (Zoom In) and F8 (Zoom Out) function keys to zoom. Zoom in and out for practice. You can also use the different Zoom icons on the View Toolbar.

Another method for Zooming In and Out is to use the Middle Mouse Scroll Wheel if you have one.

To Pan within the workspace, click and drag the Middle Mouse Scroll Wheel. The workspace image moves in the direction opposite to the dragging direction.

Press the Home key (Zoom to Full) to restore the view to the entire active schematic sheet, or use the Fit All icon.

You can also Zoom To an area by pressing the z key and dragging a box around the area.

Use the Save Zoom and Restore Zoom icons when you want to be able to go back to a previous location on the schematic.

Schematic Capture


The Find FunctionYou can move through a design by cross-probing the design hierarchy in the Navigator. You can also use the Find function.

Using the Find Function

Select Edit > Find/Replace or click the Find/Replace icon on the Main toolbar.

Click the More button to open all options.

Take time to read through the options available.

Use the drop-down Within: to define which part of the design you would like to search. In this case select Board: CORPORATE (CORPORATE).

Type C2 in the Find what: text box and click Find All.Note: The number of found items displays in the Find dialog.

Note: When you search, the results will show in the Find/Replace tab of the Output window. See item # 6 below.

Select the Output tab at the bottom of the window to activate the Output window. In the Output window, select the (component) hyperlink to quickly jump to the capacitor with reference designator instance value of C2.


Using the Find Function (continued)

Notice the section of the schematic that C2 resides within.

In the Find and Replace dialog search for 698k across the CORPORATE Schematic.

Notice all parts meeting this criterion are listed in the output window under the Find/Replace tab.

Close all of the schematic pages by selecting the name tab first, then click the small x on the sheet name tabs to close each sheet.

This method can also be used to find nets.

Now enter the net name BSYNC- (make sure to include the -character) in the Find and Replace dialog to search across the CORPORATE schematic.

Select the Find All button to search the entire schematic. There are eight instances of BSYNC- across three

schematic sheets.

Note: When selecting the net, the appropriate schematic sheet is opened and that portion of the BSYNC- net is selected. This functionality allows you to check connectivity throughout your design very efficiently.

Select File > Close Project when you are finished to close the current project.

Schematic Capture


End of Lesson. This page intentionally left blank.

Lesson 2: Creating a New SchematicThe PADS Schematic Design environment provides comprehensive schematic entry with an easy-to-use GUI. It is simple to navigate; whether you are adding borders or parts as we will experience during this exercise.

Schematic Capture

Creating a New Schematic L2-1

Creating a New Design

Click File > Open > Project and browse toC:\PADS_Stnd_Plus_Eval\PADSVX.1\Lesson5\Lesson5.prj and then the select File > New > Schematic pull down selection or select the arrow next to the New Schematic icon on the Main toolbar and then choose Schematic.

Right click the Schematic sheet name (Schematic1) in the Navigator and rename it to Logic_YourName (for example: Logic_JohnSmith).

Note: The schematic shown will be constructed during the following exercises.

Adding a Border

A border can be added automatically by selecting Setup > Settings > Schematic Editor > New Sheet from the main menubar and enabling the Automatically add border to new schematic sheets option.

NOTE: The setting Automatically adds a border to new schematic sheet box is unchecked by default.

You can also add a border manually by placing the cursor in the working area, right-click, then select the Insert Border menu selection. Note: When adding a border using this method it is taking the symbol defined in Setup > Settings > Project > Borders and Zones for the specified sheet size/orientation.

Change the sheet size of this new sheet to a C size sheet. Right-click inside the workspace and click Properties from the menu. Select the C-size from the Drawing Size drop-down in the Properties window.

Right-click inside the workspace area and select Change Border from the menu. Click the [+] sign next to the Borders item in the Change Border dialog to expand the listing. Select csheet.1 from the Borders library partition and click OK to change the border to this symbol.

Adding and Placing a BorderAdding borders into a schematic can be automatic or manual. Sometimes it is difficult to predict in advance just how much room your design might consume on a sheet (or sheets). You can start a design with a specific border size, and at any time during the design process, change the border to a size that more closely fits the design requirement. We will cover a few ways to add borders in some of the exercises that follow.

Creating a New SchematicL2-2

Placing Parts

Placing Parts into the Schematic (Manually)

Click the xDX Databook icon on the View toolbar

to open the window. Within the Symbol View (CL View Tab) of the dialog, enter RES in the filter field directly above the Symbol column header. Only symbols starting with RES are shown. Select resistor from the partition CorporateDemo.

In the Place Symbol window, place the cursor over the resistor.1 shape, hold the Left Mouse Button down and drag the symbol into the schematic working area. Release the Left Mouse Button to drop the part.

Lets add a second symbol. First select Clear Filters, then enter capn in the Symbol Filter entry. The program finds the CAPNONPOL capacitor. Select CAPNONPOL to load it in the Symbol Preview window.

Place the cursor over the symbol displayed, hold the Left Mouse Button and drag the shape into the working area. Release the Left Mouse Button to drop the part.

Schematic Capture


Placing Parts into the Schematic (continued)

Click Clear Filters, scroll down to find the CorporateDemo item and then expand the symbol list by selecting the [+] sign. Find and place symbol 145421 using the same method defined in step #4.

Find and place symbol 74192 again using same method as above.

You should now have 4 symbols on your schematic.


Adding Power and Ground Connections

Open the Settings dialog using Setup > Settings. Navigate to Project > Special Components. Then, select

Power from the dropdown menu and verify that the power.1 symbol is available from the builtin partition. (If available, go to Step 4.)

If not, click the New icon. A new dialog will open and allow you to browse the libraries for a power symbol. Select the power.1 symbol from the builtin library partition. Click OK.

Follow the same process but this time select Ground in the Special Components dialog. If the symbol gnd.1 is available from the builtin library, go to Step 5. If not, click the New icon and from the builtin library partition select gnd.1 and select OK.

Select the OK button to exit the Settings dialog. Now, on your Add toolbar you will have the Power and

Ground symbols available from the Special Components icon. Click the arrow next to the Special Components button to see the list of available components. When you place symbols from this list, they will default based on your settings from steps 3 and 4.

Select the POWER > builtin:power.1 symbol from the available choices.Note: Notice a Power pin should be on your cursor.

Left-click to place the power symbol in the working area. When you have placed it right-click to release the command.

Follow the same steps to add a Ground symbol to the schematic.

Schematic Capture


Placing Favorites and Recently Used SymbolsPlacing symbols using the My Parts window can enhance your productivity by allowing placement of commonly used symbols, along with Favorites and Recently Used symbols.

Select View > My Parts to open the window. Click the Special Components section of My Parts to review

the list of Power/Ground and other special symbols. This list provides an alternative way of placing special components. You can pick the desired symbol and drag it to place it in the workspace.

Click the Recently Used section of My Parts. Select gnd.1 and drag it to the working area and release the left mouse button at the desired location. Place one more power.1 symbol on the schematic using this method. This is an easy method to utilize symbols already placed within your schematic.

Click on the Favorites section of My Parts, then from the Symbol Preview (Place Symbol) window drag the 145421 symbol to the section. Any parts that you will use often in the schematic can be placed here so that you do not to search for them again.

Right-click the 145421 symbol in the Favorites section and click Delete item to remove it from the section.

Close the My Parts window.


Copying Symbols

We are going to need two resistors in this schematic example. Press and hold the CTRL key on your keyboard. With the key pressed use the Left Mouse Button to select and drag away from the first resistor. As you drag your mouse, a copy of the resistor will be on your cursor and ready for placement.

Using the previous method (CTRL + Left-click and drag) add two more capacitors.

Select a capacitor and create the fourth capacitor instance using Ctrl +C and Ctrl +V shortcuts.

Note: Right-click to remove the part from your cursor once the new part is placed.


Schematic Capture

ArraysThe Array feature can be used to add multiple objects.

Using Arrays

Using the Left Mouse Button, select a capacitor. Select the Array button to begin the array process. Fill in the Array box as shown: Rows = 3, Columns = 1. Click OK. The parts are automatically added and as you

drag the cursor, you can expand the array until the parts are spaced as shown (3 rows and 1 column).

Use the u hotkey or the Ctrl +Z key combination to undo this Array.


Moving, Rotating and Mirroring SymbolsThere are three ways to rotate objects within the PADS Schematic Design environment. The first is to use the Rotate button. The second way uses the F3 key during placement or move. The third way uses the options from the popup menu. You can easily mirror a symbol during placement by using the Mirror button on the Transform Toolbar, or right-click the object and select the Mirror command from the menu. Lets review a few examples.


Schematic Capture

Moving Symbols

Arrange the components as shown in the figure.

To move components, select and hold the Left Mouse Button down while the cursor is over the part you wish to move. Drag the cursor to the desired location.

Release the Left Mouse Button to drop the part.NOTE: The two capacitors located in the lower right can be deleted by selecting them and hitting the Delete key located on the keyboard.

You can select and move multiple components simultaneously. Hold down the CTRL key while selecting all desired parts with the Left Mouse Button.

Release the CTRL key, press and hold the Left Mouse Button to drag the cursor and any selected parts to a new location.

Release the Left Mouse Button to place the parts.


Rotate a Symbol

Click one of the resistors to select it. Click Rotate 90 Degrees. Note: The Rotate 90 Degrees button is located on the Transform toolbar. If the toolbar is not active, go to View > Toolbars and select Transform.

Click and hold on one of the resistors, then drag the cursor.

Note: The symbol moves with the cursor.

While you move the part, press the F3 key and notice the part rotates 90 degrees clockwise.

Release the mouse to place the rotated resistor.

Right-click on one of the capacitors, then select Transform > Rotate from the popup menu.Note: The part rotates at the cursor.

Use the u hotkey or the Ctrl + Z key combination to undo this rotation.

Flip and Mirror a Symbol

Select the IC symbol on the right.

Click the Flip icon on the Transform toolbar. This flips the entire symbol along the X-axis. Click Flip again to return the symbol to normal.

Select the same IC again, this time click the Mirror icon. Notice the Symbol now mirrors along the Y-axis. Click Mirror again to reset the symbol to normal.

Using Dynamic Grid AlignmentDynamic Alignment makes the task of arranging components easier.

Arranging Components with Dynamic Grid AlignmentYou will arrange the components similar to the picture shown.

On the Grid toolbar enable Show Alignment Markers. Select the first capacitor symbol and drag it to the desired location. Release the mouse to drop the symbol.

Select the second capacitor symbol and place as shown. Select each of the remaining capacitor symbols and note the

Dynamic Alignment Markers showing that the symbols are aligned and at the same spacing as the two symbols placed in steps 2 through 4.

Place the PWR symbols as shown and note the grid alignment markers show when the symbols are aligned in both the X and Y axis.

Place the remaining symbols as shown using the grid alignment markers.

Grid Alignment Markers can also be used to align text or other objects

Delete the two capacitors on the lower right by selecting them and pressing the Delete key.

Note: Another way to do this is to right-click and select Delete from the menu that appears.


Schematic Capture

Review Questions

1 Can I change the size of a border after I have started creating my schematic?

2 Can I mirror a symbol such as a transistor or logic gate?3 Am I limited to the PWR and GND symbols that are supplied in the library with the PADS Schematic

Design environment?

4 When would I want to create an array of components?5 Do Properties rotate with a symbol?

Review Answers

1 Sometimes it is difficult to predict in advance just how much room your design might consume on a sheet (or sheets). You can start a design with a specific border size, and at any time during the design process, change the border to a size that more closely fits the design requirement.

2 You can easily mirror a symbol during placement by using the Mirror button on the Transform Toolbar, or right-click the symbol and select the Mirror command from the menu.

3 Though the library contains a selection of PWR and GND symbols, you are free to add any custom symbols to the library that you require in your design.

4 Many designs contain groups of identical components such as switches, LEDs or decoupling capacitors. For example, some designers put all of the decoupling capacitors for a design in a group arrangement on the last page of the schematic. Using the Array command, you can place large grouping of these components with a few mouse clicks.

5 Properties do rotate with a symbol, however you must be careful when doing this if you want the visible properties to maintain a specific visual relationship to the component. In some cases, such as discrete components (capacitors, resistors, diodes), it is preferable to create a separate symbol for a horizontal orientation and the vertical orientation. This alleviates the need to make any fine tuning adjustments to the visible properties after the symbols have been placed.


Lesson 3: Component ManagementPADS Component Management is powered by xDX Databook, enabling design engineers to access all component information without data redundancy, multiple libraries or time-consuming tool overhead. This exercise will guide you through using the PADS centralized library, adding a new library, placing complete parts containing specific property data into the schematic, and verifying the component to ensure design quality, and to show you how PADS can help you get your job done right the first time.

Schematic Capture

Searches can be based on multiple parameters and display a symbol preview of the selected part.

Open xDX Databook Inside PADS Schematic Design

Note: To use xDX Databook, an ODBC data source must be created to point to the database, then xDX Databook must be attached to this data source. See the Appendix at the end of this document for details on performing the ODBC setup. These steps should be performed only once before the first use of xDX Databook.

Start xDX Designer from the Start menu to launch PADS Schematic Design environment.

Select File > Open > Project then select C:\PADS_Stnd_Plus_Eval\PADSVX.1\Lesson4\Lesson4.prj.

Component Management L3-1

Open xDX Databook Inside PADS Schematic Design (continued)

Since xDX Databook is already configured for Corporate.dbc for this exercise, we will now open the schematic and xDX Databook information pane.

In the Navigator Pane, double-click CORPORATE to enable Sheet 1.

If it is not already open, select the xDX Databook icon from the View toolbar to open the xDX Databook window pane.

Inside the xDX Databook window, click the New Search Window icon unless the Search tab already exists.

Selecting Libraries with xDX Databook

The Library dropdown list displays a list of all available libraries as described in the component information source database. All of the libraries listed are those that are defined as Tables directly in the Access Database.

Choose ICS from the Library dropdown list. Note: The system now searches the access database and lists all the components in this library.

Take a few minutes to look at the information contained for ICs. Select the scroll bar located at the bottom of the xDX Databook window and scroll the window all the way to the right. You should see a column labeled Datasheet. These are links to Datasheets that describe more about the parts.

Now choose Resistors from the Library dropdown list.


Component Selection Using a QueryWhen using a standard library configuration with traditional design tools, you must take the time to enter properties for every existence of a part. This can be very time consuming and error prone. This process may also force the creation of hundreds

Building a Component Query

Select the Query Builder button to start setting the query criteria for part selection.

With the Query Builder dialog open, select the Condition button.

Select from the dropdown list in each setting (Value, =, 10K). Select the Add button to set the criteria. The Query Builder dialog now shows the query in the lower portion of the dialog.

Select the OK button in the Query Builder to activate the search based on this criteria. The resulting data displays in the Search tab.

Note: Notice the resulting data is based on value equaling 10K.

of extra schematic symbols. In this exercise you will see how PADS Schematic Design environment reduces the need for extra symbols. You will also see how easy it is to search and select specific parts from a list of potentially thousands of parts.


Schematic Capture

Search and Place

Now narrow the search down further to Resistors with 10K Values and CC1206 cell (decal) name. Select the Query Builder again, select the AND button, select the Condition button, set the 1st field to Cell Name, set the 2nd to =, set the 3rd to CC1206 then select Add button.

Select the OK button to perform the new search based on the new criteria.Note: Notice the quantity of available parts has been reduced significantly based on the search criteria just set.

Select the Query Builder button once more, select the AND button, select the Condition button, set the 1st field to Cost, set the 2nd field to

Search and Place (continued)

The column headers can also be used to sort the results ascending or descending. In this case we have already filtered to only four results but we could have used fewer filters and then sorted the value column to find the desired part.

Select the Part 103-RES from the results display. Notice the entire line is highlighted and the symbol preview displays for the part.

While the Left Mouse Button is still pressed, drag the symbol onto the schematic and release your mouse button where you would like the resistor to be placed. You can also drag the symbol directly from the Symbol Preview window into the schematic.


Schematic Capture

View and Edit Properties

If the Properties window is not already displayed, click the Properties icon on the View toolbar

to open the Properties window. Notice how the Component Management system added all the properties to the symbol. These properties were added to the generic symbol when the part was added to the schematic. You no longer have to worry about making manual errors when adding the properties.

While in the Properties Editor, change the Value property field from 10K to 100K by entering the new value in the Value column and check the box next to the 100K value to make the value visible in the working area.

Now select and drag another schematic symbol onto the schematic sheet so the two new resistors display.

Change the Libraries: setting from Resistors to Capacitors.

Perhaps you need a decoupling capacitor but have not decided on what value of decoupling cap to use. Select any available capacitor listed in the xDX Databook pane, then click the Add New Component with only Common Properties button to add a generic component to the schematic.

With the new part active on your cursor, move both the cursor and the symbol over the working area and left-click to place the part and then right-click to finish the action.

Note: If you look at the Properties Editor, you will notice the capacitor has no Value property and is missing many other properties. You can run a complete verification to ensure all parts are compliant with the component information database.

Note: We made a unique change to a part so the part number no longer matches the defined resistance value. This condition could lead to a very expensive problem due to the way parts are ordered through a companys purchasing department. Part numbers that do not match corresponding properties generally lead to overstocks and delays in schedule. Both are costly to correct and can be avoided using Compo-nent Management in PADS. Lets look at how PADS Schematic Design environment can find these inconsistencies and resolve them quickly.


Verification

Select the Selection Filter icon located on the Main toolbar. Enable only the Symbol check box, then click the X button to close the Symbol selection box.

Use your Left Mouse Button to drag a select box around the three symbols we just added.

Click the New Live Verification Window button located in the xDX Databook display.

Note: This button is also used for verifying an entire page if no items are selected when it is activated.

A new Verify tab displays in the xDX Databook window showing the three parts color-coded.

(Yellow) Indicates a component has multiple matches. This is the generic capacitor we added.

(Green) Indicates the properties on the schematic match the database and only one part matches.

(Red) Indicates that there is a conflict between the database and the schematic and no parts match. This is the part where we changed the Value so it no longer matches the Part Number.

You will now fix the problem with the capacitor which is not correctly specified. Double click on the Yellow Circle or the part listing next to the yellow circle.

On the right hand side a search window opens up with the common properties automatically applied as filters.

Select any part listed in the search window.

Select the Annotate Component with all Properties icon to add the correct part information.

Notice the circle changes from yellow to green and the Properties window now shows the capacitor as a completely defined symbol/part.

VerificationThe PADS Schematic Design environment has the ability to run verification on a group of selected items, a single schematic

sheet, or an entire design. The functionality is similar but for this exercise you will do a verification of the parts we just placed.


Schematic Capture

Correcting Database ConflictsNow we will correct the part that we created the problem on when we changed the Value to 100K.

Correcting a Database Conflict

Double-click on the part that contains the last remain-ing red circle.

On the right hand side a window is displayed, scroll through it and notice the properties in red. Notice the Value is in red because it does not match the database.

Scroll over to Value property name, then right-click and select Remove Condition from the menu.

The system will search the database and find the part that matches the previously defined conditions. Notice that the verify routine has locked onto a single part.

Left-click the new part number.

Now select the Annotate Component with Common Properties icon to change to the new part.

We have now corrected the problem of the properties and the part number not being equal.

Note: The Properties window now shows the resistor has all the properties of the part you selected.

Select all three parts you placed using the CTRL key + Left Mouse Button.

Press the DEL key to delete the added parts.PADS combined easy-to-use libraries with powerful design and verification capabilities, to make schematic design accurate, quick and efficient. It is simple and intuitive, creating the ultimate user experience, shortens your learning curve and provides leading performance.

Do you want to experiment with PADS some more? Try another evaluation, and see how PADS can help you get your job done right the first time.


Review Questions

1 What is the advantage of using Component Management?

2 Will PADS work with my existing component database?3 How complex can I make my search parameters?4 Why use Verification?

Review Answers

1 Sorting through a library of a couple of hundred parts might be tedious, but not impossible. Doing the same for a library (or libraries) of thousands of parts would be extremely time-consuming and difficult to manage. Fortunately, PADS Schematic Design environment allows you the ability to perform very complex filtering and searches on large databases of components and presents you with a selection of candidate parts.

2 PADS Schematic Design environment will work with most ODBC-compliant databases allowing you to access the wealth of purchasing and engineering data that may already exist within your company. This connectivity also extends the capability to populate the properties of components in your design directly from the information in your company database(s).

3 You can build very complex searches so that you can quickly narrow a search of thousands of components down to a select few for consideration in your design. These searches are cumulative, so you can start out with a broad range of parameters and then add additional qualifiers until you have found the desired part.

4 When creating a schematic with a large number of symbols, it is sometimes necessary to edit values and properties as the design evolves. These changes can sometimes elude updating until later in the design process. Verification allows you to periodically compare your design database against your component database to resolve any changes or conflicts.

Schematic Capture


End of section. This page intentionally left blank.

Lesson 4: Wiring the Schematic

Connecting the Components with NetsThere are a few ways to add nets to components. This section will experiment with a few different options.

Connecting by Abutment

In PADS Schematic Design environment, click File > Open > Project and browse to the C:\PADS_Stnd_Plus_Eval\PADSVX.1\Lesson6\Lesson6.prj file. In the Navigator, expand the Blocks section and double click the schematic Logic_YourName to open this sheet.

Lets zoom in closer to the ICs. To do this select the Zoom Area icon on the View toolbar and create a frame around those two symbols. Select the smaller IC of the two ICs located in the schematic. Press and hold the Left Mouse Button, to drag the smaller IC over toward the larger IC placing the pin edges directly over each other.

Release the part by releasing the Left Mouse Button. Reselect the smaller IC again and drag it away from the larger IC.

The pins are automatically connected as we drag the second IC away from the first.

Creating Nets Using Net Mode

Select the Net icon on the Add toolbar (or enter n using the keyboard) to put the software in Add Net mode. Notice that the cursor shape changes.

Add a connection to Pin 4 of the IC located on the left hand side. Using the Left Mouse Button, select the pin and hold the button as you drag the connection to the left. When the net is long enough release the button to drop the connection.

Do the same thing for pins 5, 9, and 6 on the IC located on the left hand side.

Press ESC or select the Select icon on the Add toolbar to exit net mode.

Wiring the Schematic L4-1

Schematic Capture

Creating Nets using Multi-Net ConnectionYou can automatically connect multiple pins based on your selection order to speed up connecting your schematic.

Select the Multi-net icon from the Add toolbar. On the left IC, use frame select to select pins 14 and 19

in the order shown. Start your frame selection from the Top and to the Right of the pins. NOTE: The selection order of the nets is numbered.

To add the connections, frame select (draw the frame starting from the upper right corner) the upper pins on the two capacitors in the order you want them to be connected. Note the connection ordering numbers. Stay in Multinet connection mode and proceed to the next exercise.

NOTE: Do not right-click to exit the command.

Manually selecting Multiple Pins

While still in the Multi-net connection mode, select pin 7 on the left IC.

While pressing the CTRL key, also select pins 12 and 11. Note the ordering.

Now release the CTRL key and select Pin 2 of the lower left resistor, then select Pins 1 and 2 of the upper left resistor in the proper order as shown.

Right-click to exit the Multi-net connection command.

Click the Undo icon from the Main toolbar to remove these connections so you can practice connecting the nets outside of net mode in the next segment.

Wiring the SchematicL4-2

Creating Nets Outside of Net Mode

For the IC on the left hand side, right-click the left side of pin 7.

Move the cursor to the resistor located next to it on its lower left hand side.

Note: As you move the cursor, a net is added and follows the cursor.

Left-click to select the resistors upper pin to connect the net to it.

Create the connections as shown on the schematic. Do not worry about assigning signal names at this point. You will do that next.

Schematic Capture


Naming Nets and Placing Labels

Naming Nets

Double-click the Net from pin 13 of the IC symbol on the left side (bottom of device).

Note: If you have difficulty selecting a net, enable Name, Net and Bus in the Selection Filter.

The Properties window opens. Enter the name C/BE3. Select the net name in the working area and drag it to

the left of the net.

NOTE: If you move the net when attempting to move the label, then you have the net selected in addition to the label. Try zooming in closer or using the Selection Filter to enable Name.

Double-click the net connection from pin 21, then name this signal C/BE2.

Click in an open area to release the signal name and the selected connection.

Now select the signal name again, and drag the signal name to its desired location.


Adding Names Using the Navigator

In the schematic, select the net connected to pin 4 of the IC on the left. The corresponding net in the Navigator highlights.

In the Navigator, right-click Rename, then enter the desired name and press Enter. Rename the net connected to pin 4 to ~CE. Using a ~ will create an inverted pin name.

Another way to set pin inversion is to use True/False in the Properties window.

Schematic Capture


Adding Symbols with Named Net StubsYou can also add nets when you place symbols in the schematic.

Start by checking to see if the xDX Databook window is displayed in your xDX Designer workspace. If not, select the xDX Databook icon from the View toolbar to activate this pane.

Click the Search tab in the lower left corner of the xDX Databook window, then select the ICS library from the dropdown list. Select the part with the Part Number attribute equal to 74HC192.NOTE: Searching is case sensitive.

Before placing the symbol on the schematic, click Add Component with Net Stubs and Add Pin Labels To Nets icons on the left side of the Symbol viewer.

Click Add New Component With All Properties icon and click the desired location to place the component on the schematic.

Notice that all pins have net stubs connected and they are all named according to the corresponding to the pin.


Setting Properties for Parts

Property Visibility

Check that the Properties window is active in your workspace. If not, open the Properties window by selecting the Properties icon on the View toolbar or by double-clicking the desired object.

Select the IC on the left side.Note: If you have difficulty selecting a part, enable Symbols in the Selection Filter.Note: The properties for this component display in the Properties window.

Every property has a Property Name and Property Value that is displayed in the Property and Value columns of the Properties window. To make a property name visible on the schematic, you enable the check box next to the property name in the Property column. Notice the checkbox next to the Ref Designator property name in the window.

Enable the check box next to the Ref Designator property name. Notice Ref Designator is now shown below the symbol. To make only the value visible enable the check box next to U? and disable the box next to Ref Designator. Now only the value U? is visible.

Schematic Capture


Adding New Properties

To add a new property on the schematic the property must be enabled/defined in the Property Definition Editor inside library management.(To do this, click the xDM Library Tools icon on the Main toolbar and then select Tools > Property Definition Editor). This helps users standardize on required properties within the company and also prevents typing mistakes. Take a look at the properties available and then click Cancel to close the Property Definition Editor and exit xDM Library Tools.NOTE: If any new Properties are required in your designs, you must define them in xDM Library Tools first. After making a change, you will have to run Tools > Update Libraries or exit and re-invoke PADS Schematic Design environment before the properties are available for assignment.

Make sure the Properties window is open and the IC on the left is still selected before adding the new property. In the Properties window click in the blank cell at the bottom of the list and select Company Part Number from the list.

Enter 510_5V_IC for Value. Select the IC on the right side of the schematic.

Enter the following property information:

Company Part Number = 506_5V_IC DATASHEET = C:\PADS_Stnd_Plus_Eval\PADSVX.1\

Datasheets\CD54HC192.PDFNote: This last step links the part to a datasheet. A link can be made to any type of document or website. The document can be launched directly from the schematic.

Select the symbol and then right-click and choose Open Hyperlink > Datasheet.Note: This opens the appropriate datasheet in Adobe Acrobat.

In Adobe Acrobat, close the datasheet.


Change/Edit Properties

Select the resistor on the bottom left.

Add or change the following properties:

Part Number RESISTOR1206

Company Part Number 107-RES

Cell Name CC1206

Value 5.1K

Tolerance 1%

Power 250mW

Select the resistor on the top left.

Add or change the following properties:

Part Number RESISTOR1206

Company Part Number 101-RES

Cell Name CC1206

Value 10K

Tolerance 1%

Power 250mW

Schematic Capture


Adding Properties to Parts Simultaneously

Select the top left capacitor.

CTRL + click each of the other two capacitors.

Note: All three of the capacitors are selected and their properties are listed in the Properties window.

In the Properties window click in the blank cell at the bottom of the list to add a new property.

In the Property column select Company Part Number. In the Value column field (directly across from the

Company Part Number property) enter the property value of 12301-CAP.

Press Enter to complete the property assignment. Now if you select each capacitor individually you will notice they all have the same Company Part Number property.

Add the following properties to all three capacitors.

Part Number CAPNONPOL

Cell Name CC1206

Value 10U

Tolerance 5%

Voltage 16V

When you have finished adding the properties, review the assignment on each individual part, then close the schematic sheet.


Working with the Bus Model

Creating a Bus

On the Main toolbar, click the arrow next to the New Schematic icon, then select Schematic from the drop-down list to begin a new schematic.

The new schematic is in the Blocks section on the Project Navigator and is called Schematic1.

Place 2 instances of the symbol SymbolTest. Check that your xDX Databook window is displayed (if not, select the xDX Databook icon from the Main toolbar). Select the Show CL View icon on the left hand side of the xDX Databook window, then switch to the Symbol View tab in the upper left corner.

Expand the CorporateDemo library partition using the [+]character, find and highlight the SymbolTest symbol. Note: You could also enter SymbolTest into the search field above the results display area and let xDX Databook find any matches in the list of libraries.

Click the Place Symbol button in the Symbol Preview window to place them on the schematic.

Right-click to release the cursor from Placement mode.

Next, zoom in to the left side of the symbols.

Using the Bus icon on the Add toolbar, place a vertical bus to the left of the symbols and press Esc to exit the command.

Label the bus by assigning the A[15:0] value to the Name property for the bus inside the Properties dialog.


Connecting a Bus to Component NetsThere are 2 ways to connect these symbols to this bus. The first method connects the nets from the bus to the component.

Position the cursor over the created bus segment and right-click (directly across from the pin 2 on the left, below CLK) where you want the first net to connect and click Rip Nets. NOTE: If you do not see the Rip Nets menu pick then you may need to click into the design view to unselect the bus and then try again.

Select the nets you want to use using CTRL + Click or Shift + Click methods. In this example, we are going to use A[15:8] from the Rip Nets dialog to connect to the top symbol.

Click OK to place the nets on the bus starting where you last clicked. Use the CTRL+SHIFT+Mouse Scroll Wheel to spread the Bus Bits as needed. When the net lines are in-line and touching the symbol pins, click to connect them.

NOTE: Verify that the Grid is enabled (Grid On) .


Connecting Component Nets to a BusThis is the second way to connect these symbols to this bus. This method connects the nets from the component to the bus.

Select the bus nets you added in the previous steps using the CTRL + Click method.

Click the Copy icon on the Main toolbar to place the nets on the clipboard.

Zoom the schematic to the second IC. Click the Paste icon, and move the pasted nets to the location as shown. When the net line ends are aligned with the second IC pins, click to connect the nets to the IC. Press the ESC key on your keyboard to exit the command and to select the added nets.Note: The Connection indicators (*) help to adjust the nets into place.

Use the Add Properties Mode icon on the View toolbar to invoke the Add Properties dialog box, and set the following.

Type = Net

Property = Name

Range = Enabled Prefix = A

Value Dec= 7 and Delta = -1This names all of the nets and allows you to use the cursor to drag them to connect up to the bus.

Click Apply to place the Bus Bits.

Click on one of the nets to drag them towards the bus. When the nets are over the bus, release the left mouse button to connect them.

Close Add Properties dialog.

Schematic Capture


Review Questions

1 Do I need to connect every net at all points?

2 Why add names to nets?3 Which properties should I make visible in my designs?4 When would I add properties to parts simultaneously?5 Why would I use a bus to represent connectivity of multiple connections?

Review Answers

1 As long as the schematic accurately represents the desired connectivity, it is not necessary to connect every net to all points. Connectivity can be established by naming the nets, and as long as all net stubs are identically named, connectivity will exist.

2 In addition to establishing connectivity, net names also help identify signals in very complex designs. Some designers will name their nets with a convention that represents the source and destination of the net (such as FPGA_A\S3_A_MEM_A_ADDR0). This makes it easy to identify the purpose and connectivity of a net just by examining the name.

3 Which properties you choose to make visible is primarily a decision based upon the intent of the document. Most designers choose to have reference designators (Ref Designator) visible along with component values, tolerances, wattages and component names. This is a very individual decision and each company may find it necessary to set their own standard. The PADS Schematic Design environment allows you to set the visibility of properties down to the individual component level.

4 If your design contains a quantity of identical components, it may save a lot of time if you select the group of components (either in the workspace or through the Navigator) and then assign/change the properties for all of the components simultaneously. This helps to promote uniformity and continuity across the design. Remember to verify the components when you have finished the design.

5 Connectivity can be accomplished by using individual nets to connect each point, or by naming each of the nets. Showing all of the connections on a schematic can make the schematic difficult to read and add unnecessary visual clutter. An alternative is to use a bus to represent a group of nets (such as an address or data bus) that connect to a number of points (or sheets). This allows you to show the connections at the components but represent the group across the design with a single (wide) net line. The bus is identified with a label that shows all of the signals represented by the bus (such as ADDR_BUS_0:15).


Pre-Layout Analysis

In This Section:

Pre-Layout Signal Integrity Analysis

HyperLynx LineSim is a pre-layout PCB design simulation and analysis tool that enables you to evaluate the signal integrity performance of signal nets. In this exercise, you will experience the process of selecting a net for simulation, reviewing Simulation Models assigned in PADS Schematic Design environment, selecting a net for analysis, perform an analysis and save the analysis results for future use.

Lesson 5: Pre-Layout Signal Integrity Analysis

Pre-Layout Analysis

LineSim LinkLineSim Link can export a net to HyperLynx LineSim for pre-layout simulation.

In PADS Schematic Design environment select File > Open > Project and select C:\PADS_Stnd_Plus_Eval\PADSVX.1\Lesson10\Lesson10.prj.

In the Project Navigator, double-click the Lesson 10 board, then double-click the CORPORATE schematic to display the list of schematic sheets.

Now double-click the Memory schematic sheet in the Project Navigator.

Zoom to the upper left IC shown on the Memory sheet. Select the IC U15.

Note: Set the Selection Filter to Symbol if necessary.

In the Properties window, review the assigned Simulation IBIS models: SIM_MODEL and SIM_MODEL_FILE. (You may need to scroll down to see them).

Note: If the Properties Window is not visible, click the

Properties icon on the View toolbar.

Pre-Layout Signal Integrity Analysis L5-1

LineSim Link (continued)

Make sure that the Net and Bus item is enabled in the Selection Filter. Select the net DATA_BUS0 starting from U15.13. Right-click and choose LineSim Link.

In the LineSim Link dialog, enable Complete schematic (export including interconnections) in the Schematic Contents section, then click Load Data from xDX Designer. Note: You can change parameters to the Transmission Line Properties. We will not make any changes and use the default settings.

In the Schematic Topology tab, review the drivers and receivers for this net. Expand both Electrical Net 1 and DATABUS0 by selecting the [+] next to each of them. Note: U13 is set as a driver, and U15 and U26 are receivers.

Select U15.13 in the DATA_BUS0 Electrical Net sub-tree and select the up arrow icon to move the topology to match the order as shown in the image below.

On the Options tab, select Export to HyperLynx. Click Yes to overwrite existing files, if needed.

Pre-Layout Signal Integrity AnalysisL5-2

Launch HyperLynx LineSim

PADS Analysis will open with the DATA_BUS0 net loaded into the LineSim Free-Form Schematic Editor for simulation using the models assigned in PADS Schematic Design environment.

In HyperLynx, select the Edit Stackup icon. Review the cross section of the 6 layer board, then close the Stackup Editor.


Pre-Layout Analysis

Assigning Models

You need to assign a missing model to U13. Select U13, right-click, and select Assign Models.

In Assign Models, click Select.

In Select IC Model, choose xc9500.ibs from the Libraries list, and then choose XC95216_BGA352[SLW=0;VIO=0] from the Devices list, then click OK.

In Assign Models, select U13.io pins and change the Buffer settings to Output.

Click OK. All of the models are assigned and are ready for simulation.


Run Net Simulation

Click Run Interactive Simulation, the Digital Oscilloscope window opens. Select Rising Edge. Make sure different colors are assigned to the probes, and select Start Simulation.

In the Digital Oscilloscope window, on the waveform, select the top and bottom of the overshoot of the waveform to review the span of the voltage overshoot. (For Example, Receivers have overshoot of about 2.1V.).

We want to save the results of the simulation for future use with the routed board. In the Digital Oscilloscope window, select the Save/Load button, select the HyperLynx .LIS radio button and then click the Save As button. Save the file with name DATA_BUS0_no_termination.lis.Click Yes to replace the existing file if it exists.

Close the Load/Save Waveforms dialog box.

Pre-Layout Analysis


Running Terminator Wizard

To fix the Signal Integrity problems, add RC Termination to the U15.13 receiver. Click Add RC Terminator to the schematic and position the top of the resistor so

that it touches the left blue dot at the output of TL2 . To assign values to the terminators, click the Run

Terminator Wizard icon. Choose 5% from the Apply Tolerance dropdown list.

Click Apply Values, then click OK. The value is assigned to the terminators. Notice how HyperLynx automati-cally calculates the resistance of R1 to be 75 ohms and the capacitance of the C1 to be 160.0 pF.



Pre-Layout Analysis

Erasing Results and Rerunning Simulation

In the Digital Oscilloscope window, click Erase and rerun the simulation with RC Termination and the values assigned. You will notice that we cut down the overshoot by more than double (about 1.25V). We can continue to refine if necessary.

Save the results as we did in Running Net Simulation (Step 3) with file name: DATA_BUS0_terminated.lis. Click Yes to replace the existing file if it already exists.

Close Digital Oscilloscope and exit HyperLynx LineSim. Click Yes to save changes, then select File > Close Project.

PADS combines easy-to-use schematic design with powerful verification capabilities for pre-layout analysis to make schematic design accurate, quick and efficient. Use PADS to model critical signals in your design and predict its behaviour in the final board design. PADS can even suggest possible modifications with an advanced wizard, making your PCB design process simple and intuitive, and provides leading performance.

Do you want to experiment with PADS some more? Try another evaluation, and see how PADS can help you get your job done right the first time.

Review Questions

1 When would I want to use HyperLynx LineSim?

2 How does HyperLynx LineSim know how the signal will perform on the printed circuit board?3 How does HyperLynx LineSim fix signals that dont perform as expected?4 Does HyperLynx LineSim select the actual components for terminators?

Review Answers

1 HyperLynx LineSim lets you model critical signals in your design and attempts to predict their expected behavior in the final board design. You can model a signal, use the tool to experiment with corrective measures and save the simulations for future results comparisons.

2 HyperLynx LineSim uses industry standard component models to predict signal behaviors along with sophisticated internal algorithms and proprietary technologies.

3 HyperLynx LineSim features wizards that can suggest possible modifications to your signal chain to correct aberrations and performance issues. Simply run the Wizard and the system will present you with suggestions to correct signal integrity issues.

4 HyperLynx LineSim offers suggested values for terminators, not specific part numbers. It is up to the user to determine which manufacturers part number will meet the required specifications for the design.


Library Management

In This Section:

Working with PADS Library Management

The key to successful PCB design is ensuring that the physical design data matches the logical intent of the design. PADS provides a common interface for managing the various elements that make up the library objects like schematic symbols, cells (physical decals) and part definitions. Managing relationships between library objects ensures the design is correct by construction. The library management interface is where you create/edit library objects and maintain the relationships between these objects.

Lesson 6: Working with PADS Library Management

Library Management

Working with PADS Library Management L6-1

Objects in your Library may be partitioned into related groups. Changes made to one object affecting another object are propagated automatically. Built-in data checking ensures the relationships between objects are valid and that objects cannot be deleted if used by other objects. This tight integration ensures data reliability throughout the library development and design processes.

This lesson will give you the basics of what PADS Library Management can do for you.

Working with PADS Library ManagementL6-2

Opening Library Manager

You can open Library Manager from within the PADS Schematic Design environment or within the PADS Layout environment.

Start xDX Designer. Select File > Open > Project from the menubar to

open C:\PADS_Stnd_Plus_Eval\PADSVX.1\Lesson15\Lesson15.prj.

Select Tools > xDM Library Tools from the menubar to open the interface. The library associated with the Lesson15 project will be loaded. The name of this library is CorporateDemo_CentralLibrary.

Library Management


Library Manager Workspace

The Library Manager interface is used for library management and editing. It contains utilities that are specific to the PADS Flow and provides access to editing tools for library component creation.

Review the main areas shown. There is one menubar and one Standard toolbar. Workspace elements can be enabled/disabled using the View menu commands.

Use the Library Navigator Tree to explore the library structure which consists of different partitions for each of the top-level library sections:

Parts definitions of physical parts Decals physical decals (footprints)

Symbols schematic symbols

Drawings free-form drawings, reusable copper shapes, board outlines Models models used for simulation.

Expand and review the library sections. Objects inside each section are organized in user-defined groups called Partitions. Each top-level section shows the same list of partitions. If you hover with the cursor over a partition you see a tooltip indicating the number of objects inside the partition.

Menus Toolbar Workspace

Library Navigator

Tree

Status Bar


Finding Objects in a Library

The library management environment provides basic capabilities for searching all library objects. The scope of search depends on how you activate the Find command. Wild cards (*, ?) are supported.

Select the CorporateDemo_CentralLibrary entry in the Library Navigator Tree, right-click, then select the Find command from the menu. This opens the Find dialog. Notice that the Search for: filter is set to Any Type of Object.

Type D* in the Name box and click OK to initiate the search for all objects that start with D. The search results in finding the DIN96 part inside the CorporateDemo partition.

Right-click DIN96, then select Find Next from the menu. This time the DS26C31C part is found inside the mixsig partition.

Library Management


Finding Objects in a Library (continued)

Now, select the Decals branch in the Library Navigator Tree, right-click, then select the Find command from the popup menu. Notice, that this time, the Search for: filter is set to Decal.

Click OK to initiate the search. The search results in finding decal DCAP_SR21 inside the CorporateDemo partition.


Creating a New Partition in Your Library

In this exercise you will go through the process of creating a part from start to finish. You will create a partition, new schematic symbol, physical decal and map them together to a part.

In the Library Navigator Tree, right-click the Parts listing and select New Partition from the menu.

In the New Partition dialog box, specify New_Partition as a name for this partition. Click OK to close the dialog.

Expand top-level sections (Parts, Decals, Symbols) inside the Library Navigator Tree and check that the New_Partition is listed in all these sections.

Library Management


Creating a New Schematic Symbol

Creating and placing all of the pins manually on large pin count devices can be tedious and error prone. By entering all your pins into a spreadsheet, you can quickly and easily import them into the Symbol Editor to generate the symbol graphics.

Select the Symbol Editor icon from the toolbar. This will open the Symbol Editor interface.

Select File > Preferences from the main menu to review and adjust settings affecting the symbol generation in the Preferences dialog.

Select the General page on the left hand side of the dialog. Inspect the Grid settings: Grid readout should be enabled, Grid step should be 0.1 inch, set the Large Dot every to 1. In the Pins section, Default length should be 2 and Default spacing should be 1.

Click Apply to make changes and to keep the dialog open.


Creating a New Schematic Symbol (continued)

Switch to the Appearance page and select the Pin Label from the Subcategory list. Set font size to 8, then select the Property Text subcategory and set font size to 8. Click OK to apply changes and to close the dialog.

NOTE: The screenshots in this guide are pre-set with a white page color background. Should you wish to change from the default black background in your personal design environment, select the Appearance listing and then select the Page Color subcategory to change the color from black to white for your Symbol Window.

Select File > Generate Symbol from Pins on the main menu. This opens the Select pin list file where you navigate to the C:\PADS_Stnd_Plus_Eval\PADSVX.1\Libs folder and open the New_Symbol.csv file. A symbol is created automatically in the working area of the symbol editor. Note: If you open the New_Symbol.csv file in a spreadsheet editor (like MS Excel) you can review the data stored in the file.

Library Management



Delete power and ground pins (pin 1 and pin 22). To do this, enable pin selection (if not already enabled) by clicking the Select Pins icon on the Main toolbar, then select pin 22 and press and hold the CTRL key and then select pin 1 in the Pins area. Release the CTRL key and press the Delete key to delete these two pins.

Select File > Save As from the main menu to save the symbol to library. This opens the Save Symbol dialog.

Inside the dialog, select the New_Partition and use New_Symbol.1 as a symbol name. Click Save to close the dialog.

Select File > Exit to close the Symbol Editor and to return to the Library Manager.



Inside the Library Navigator Tree expand the New_Partition branch under Symbols to check that the New_Symbol is listed. Right-click New_Symbol, then select Preview from the menu. This opens symbol preview window with the New_Symbol loaded. Close the preview window.

Library Management


Creating a Footprint

To complete the creation of a new library component you need to create a footprint and a part definition.

Select and expand the Decals branch inside the Library Navigator Tree, right-click the New_Partition item and select New Decal from the popup menu.

The New Decal dialog displays. Type NEW_DECAL as the decal name and click OK to close the dialog. The PADS Decal Editor opens.

In the Decal Editor you can create a PCB decal manually, however for this exercise youll be using the decal wizard that greatly simplifies de

pads standard plus evaluation guide

Documents

liability of mentor

pads standard

guided tour of pads

government license rights

enduser license agreement

service marks marks

routing routing

government subcontractor