EXPERIMENT NO:1 Date: INTRODUCTION TO PCB DESIGN

OBJECTIVE: To learn and understand Printed Circuit Board Technology terms and definations. To obtain an overview of the PCB design process and the various steps involved.

HARDWARE/SOFTWARE REQUIRED: Computer with following configuration P4 processor, 160gb Hard-disk, 1gb of RAM Power Logic and Power PCB installed in the computer

1. PCB Board TypesSingle Sided Board- Traces appear only one side(usually the solder side),Components are inserted on the component side. Holes on the single sided board are non-plated through hole(NPTH).

Double Sided Board- Traces appear on component and solder sides. The walls of the drilled holes in circuit boards are copper plated (aka Plated Through Holes, PTH) to allow top and bottom circuitry to be electrically interconnected.

Multi-layer Board- As the density and complexity of electronic circuits increase, PCB’s come in multi-layered boards. Layers of circuitry are sandwiched together.

2.Through Hole and SMDThrough Hole Technology(THT)- refers to through-hole mounting of component’s(IC’s, resistors, capacitors, connectors etc…). The following diagram shows examples of DIP(Dual In-Line Package) component’s, which are through hole components.

The pin pitch(pin to pin distance) of DIP packages is 100 mils (0.1inch or 2.54mm). The unit of mils(thousandth of an inch) is still widely used in the industry. Take note of these numbers on a PCB design with through hole technology, one side of the board where the components are mounted is known as the component side. The other side of the board where solder is applied to solder the component onto the PCB is known as the solder side.Surface Mount Technology(SMT)- Component’s( IC’s, resistors, capacitors etc…) are soldered to the pads on the surface of a board without through holes. Following diagram shows a PLCC(Plastic Leaded Chip Carrier) package which is one example of many types of surface mount components such as SOIC(Small Outline IC), SOJ(Small Outline J-lead), FP(Flat Pack), QFP(Quad Flat Pack)etc…SOIC and PLCC has pin pitch of 50 mils as compared to 100mils on a DIP package. The smaller component sizes, lack of through-holes, and possibility of mounting chips on both sides of the PCB improve the board density.

Surface-mount component’s are usually smaller than their counterparts with leads, and are designed to be handled by machines rather than by humans.A typical SMD resistor has dimensions like this:0603(1608 metric): 0.063’ * 0.031 (1.6mm * 0.8 mm). The typical power rating for such resistor is 1/16 watt3.PCB TerminologyTraces are copper tracks on the PCB that carry signals.Planes usually refer to power/ground planes such as VCC,VDD,VSS,GROUND etc… Instead of using copper traces to connect power/ground pins of the components, a solid copper layer is used as the power/ground plane. One of the advantages of using power/ground plane is reduction of power/ground noise voltage.

Pads are for soldering of component’s pins. For through hole component on a multi-layer(4,6,8,10…) board, each pin has a pad on each copper layer which form a pad stack. Following diagram shows the padstacks for different types of pins of a 74LS00 IC on a 4-layer PCB.Please note the shape of the thermal relief pads used to connect to power/ground plane.Plated through holes are holes with copper plating on the wall of the holes. The copper plating allows pads on different copper layers to be interconnected. For through hole component, each pin requires a plated through hole so that it could be inserted and soldered onto the PCBNon-plated through holes are usually meant for mechanically assembly. In this case, there is no copper plating in the drilled hole Vs are for interconnecting traces on different copper layers. It is layer of plated through hole but is usually smaller and not meant for mounting and soldering of component. Following diagram show different types of vias.

Guides are also known as rat nest. It is used in the PCB layout software to show a connection between 2 pins with a straight line. A guide only indicates a connection between 2 pins. It disappears as soon as pins are connected by copper trace. It is useful in guiding the PCB designer in manual routing.

PCB LayoutIt is also useful in determining how good the placement of the components is before the board is routed.Reference designator (R1,R2,….C1,C2,…. Ui,U2) is a unique identifier assigned to each component on a PCB for easy referencing.

Trace

4.Various types of layers are found on a PCBSignal layers are for routing of copper traces for interconnection of component’s. Power layers are for dedicated power/ground planes.Solder plating layers are usually applied to the top and bottom signal layers to prevent oxidization of copper traces. Usually Tin or Gold plated.Solder mask layers prevents solder flow to the component’s pins during wave soldering process. Polymer prevents bridging of solder when pads are near to each other.Silkscreen layer is usually printed on the component side of the board for displaying shapes and position of components, reference designators and text (such as board revision,data etc)When determining the number of layers of the multi-layer PCB, only count the copper layers(i.e. signals and power layers).5.PCB Design Process

6.Part CreationPart creation is a process of creating a component that contains a CAE Decal and a PCB Decal. The CAE Decal created is used in the schematic capture process while the PCB Decal is used in the layout process. CAE Decal is the logical representation of a component, PCB Decal is the physical footprint of the component.

e.g. Note that part creation is only necessary when the component is not found in the component libraries. Commonly used components such as the 74 series of IC’s, resistors, capacitors etc are available in the standard libraries. In addition users can create their own components( if they are not found in the standard libraries) and save them in their own libraries.7. Schematic Capture

Schematic capture is a process of drawing the circuit diagram of a given electronic circuit. Output of the schematic capture software is a ASCII text file known as NETLIST. Example of a net list file is shown below:

Any wire that connects 2 pins is called a net and is given a net name. Net list gives the parts and packages used in design, as well as the connections between parts/pins. In drawing the schematic diagram, 2 or more pins can be connected by either physical wire or by using the same net name.8.LayoutLayout is a process of placing the components on the pcb and routing the copper traces to connect from pin to pin.-Component placement can either be automatic or interactive but usually it is done interactively as the pcb designer knows where is the best location to place a component.-A good placement of the components on the pcb is essential for a good and speedy routing. A good placement minimizes the traces length ;no of vias required and reduces the routing time.-Swapping is the ability to swap the position of similar components to achieve shortest overall traces length and minimize routing complexity.-Routing traces on the pcb can be done automatically or manually.Routing is govern by design rules which define the trace width and the clearance rules-It is important to note that sometimes the auto router software cannot finish the route, i.e not 100% routed in such cases ,it is necessary to finish the connection by manual routing.-Sometimes it is necessary to insert a via to cut across traces9.Considerations for routing

minimizes use of wires Minimizes bends and avid sharp corners.

Avoid having parallel traces close to one another for high frequency signals. this will prevent cross-talk.

it is a good practice to route traces vertically on signal layer and horizontally on another layer to prevent cross talk.

avoid having unnecessary long traces which leads to delay in signals Increase the trace width for high current traces. Ensure good grounding. Use ground plane if possible to reduce ground noise. Observe all design rules.

Pattern routing is one of the many types of routing algorithm. It is primarily used in routing memory devices where the same pin number of the devices is to be connected together.

10.Forward/Backward annotationbackward annotation is a process of updating the schematic database with changes generated frm the layout process.Another example is when the pins/gates/components are swapped in the layout, the changes has to be back annoted to the schematic database.Forward annotation is the process whereby parts and connection in the PCB layout are updated after changes are made in the schematic capture.11. Post Processing Post processing refers to the various processes that are carried out after the PCB has been routed. It includes generation of PCB artworks ( CAM files), drill data , bill of material(SCM).PCB artworks are usually plotted by an equipment call photo-plotter. The standard PCB artwork data file is in Gerber Format.Drill data is used by the NC machine for automatic drilling of holes. The company that first produces such machines is Excellon.BOM (Bill of Material) is generated to facilitate purchasing of parts for board assembly.12.PCB Fabrication and Board AssemblyPCB Fabrication PCB boards are produced by selectively removing unwanted copper on the board. For example, you can order a single-sided board with 1 oz/ft2 copper on a 1/8” thick FR4 substrate (Fibre-glass composite board) and excess copper can be removed by either:-Mechanical Milling(prototyping, small production runs)- Acid Etching(mass production)

1 The copper board is covered with a protective polymer (Called photo-resist)2 types of resist Positive and Negative, Positive resist Parts exposed to UV light, will be removed Negative resist Parts not exposed will be removed

Laminated Board With Resist2 The desired Printed Circuit

is patterned on the photoresist by a process called photolithographyYour artwork will first be printed onto a photographic film by using a photoplotter.

It will be used as a mask.The picture on the right shows a Positive mask, UV light will pass through the transparent parts of the film

Mask

3 The mask is placed on top of the resist and exposed to UV light

Mask on Laminated Board

4 The positive resist, exposed to UV light breaks down and can be washed away using a developer.Common developer, Sodium Hydroxide(NaOH) for positive resist and Sodium carbonate (Na2CO2) for negative resist

After Developing- Removal of Resist5 The resist, not exposed to

UV light , protects the desired printed circuit pattern,The unwanted copper is etched away using chemicals like: Ferro Chloride(FeCl3) or Sodium Persulfate(Na2S2O8)After some time, the unwanted copper will be removed, leaving the copper coated with resist.

After Etching – Removal of Unwanted Copper

6 The resist is finally removed, using a resist stripper. Copper circuit patterns will be left on the board. Thereafter -Holes can be drilled -Copper and tin can be added to the tracks by electrolytic process-Solder resist can be applied-The silkscreen can be printed.

After Resist Removal-Barn Copper

PCB Assembly- Once the PCB boards are ready, the components are inserted or placed on the board either nby machine or hand. In massproduction, soldering of components onto PCB boards is usually done by:Wave soldering: PCB board is placed on a conveyor be soldered touches a pool of molten solder belt. The parts that are to be soldered touches a pool of molted solder.Re-flow slodering(preferred for SMD); Solder is applied onto the pads and then the SMDs are placed onto them. The board goes through an oven which melts the solder.POST LAB QUESTION:1. For a double sided board, how many Cam files do you need to generate? List all the necessary Cam

files.2. Upon completion of the PCB placement and routing, what are the checks that we should perform on

the entire board?3. Why is it necessary to create a net-list in Power logic?4. What are the steps that we should take to minimize unnecessary long traces in the printed circuit

board design?5. What is a design rule? Should we set the design rules before or after components placement. Justify

your answer.

Result: Hence the terminologies and the components used in the PCB design are studied.

EXPERIMENT 2 Date:Introduction to POWER LOGIC

OBJECTIVE: Learn to create a schematic drawing with Power Logic. Learn to design a PCB layout using Power PCB.

Learn to generate CAM filesHARDWARE/SOFTWARE REQUIRED:

Computer with following configuration P4 processor, 160gb Hard-disk, 1gb of RAM Power Logic and Power PCB installed in the computer

PROCEDURE Launch Power Logic. Note: A Status window automatically appears on the left side of the screen when starting the Power Logic. Close this window for now by clicking the window close icon.Drafting ToolboxSelect the Drafting icon. Another group of icons appear. This is called the Toolbox. There are many functions under the drafting toolbox they are

Add Text Create 2D line Modify 2D line Combine/Uncombined Add from Library Save to Library

Set Units of MeasureChange the unit of measure to inches, mils(default setting), or metric units by Prefereces

Select Setup in the task bar Then select Preferences to change the measurements The design unit settings are on the Global tab of the preferences dialog box. Set the units of

measure of mils.

Set Display and Design Grids Change both the design grid and display grid to 100 mils Select Setup from Task bar Then select Preferences Then Grid

Design PCB Schematic Using Power Logic Select Design in the toolbar Then select Add Part Then select parts from the Library After selecting all the parts connect them using Add Connection

Generation of NET-LISTA net list is the typical method for passing schematic data into Power PCB as layout data. A net list contains a list of parts and their part types and all the nets(connections).

After creating the schematic go to tools in the main menu Click on the Net list to PCB The file will be saved default folder The file will have an extension of .asc with the file name as ExcerciseA

BOM(Bill of Materials) Choose File from the main menu. Click Bill of Materials Click on the Setup Use Add Button to add the header fields Set the corresponding attributes as: ITEM,QTY,REF-DES,PART-TYPE, Value and

Manufacturer Click apply on the reports menu and notepad will display the BOM The file is automatically saved in default folder.

Post Lab Question:6. Explain the difference between design grid and display grid in Power logic and Power PCB

environment.7. What is Bill of Material (BOM)?8. What is the information that display in silkscreen layer?9. What are the considerations for routing a printed circuit board?10. Fill in the blank in the below PCB design flow.

Result:Hence the Power Logic Introduction has been done successfully and generated the BOM and net-list.

EXPERIMENT 3 Date:Introduction to POWER PCB

OBJECTIVE Introduction to Power PCB Importing Net-list Schematic-Driven Placement with Power Logic

Routing Creating CAM files

HARDWARE / SOFTWARE REQUIRED: Computer with following configuration P4 processor, 160gb Hard-disk, 1gb of RAM Power Logic and Power PCB installed in the computer

PROCEDUREDrafting ToolboxSelect the Drafting icon. Another group of icons appear. This is called the Toolbox. There are many functions under the drafting toolbox they are

2D line Copper Copper cutout Copper pour Copper pour cutout Board outline and cutout Keep out Add text Flood etc…

Set Units of MeasureChange the unit of measure to inches, mils (default setting), or metric units by Preferences

Select Setup in the task bar Then select Preferences to change the measurements The design unit settings are on the Global tab of the preferences dialog box. Set the units of

measure of mils.

Set Display and Design Grids Change both the design grid and display grid to 100 mils Select Setup from Task bar Then select Preferences Then Grid

Importing NET-LIST Choose File Click on Import Click on yes button when prompted to save the old file before loading Navigate to file directory and open the NET-LIST generated using Power Logic

Moving Components using Disperse Components Use the Disperse components choose Tools Click on disperse components and confirm the dispersion

Define Design Rules Design rules include clearance, routing and high speed constraints assigned as default conditions or for nets, layers, classes or pin pairs. The 3 sets of design rules are

Default Clearance Rules Default Routing Rules Net Clearance Rules

Set Default Clearance Rules Choose Setup Design Rules Click on default icon Choose clearance icon

set all the Clearance value to 12 and change the Trace width to 10,12,15 respectivelySet Default Routing Rules

To minimize the total length of all pin pairs, perform the following setup From main menu select setup Click on Design rules Then click on Default >> Routing >> Total Length Click OK and close all dialog boxes

Set Net Clearance Rules From main menu select setup >> Design Rules – Net Use control Click to select both +5V and GND Choose clearance icon Set all the clearance values to 18 and Trace width values to 15,18,20 respectively

Schematic-Driven Placement with Power Logic Choose window in the main menu Click on toolbars and then object selector Object selector toolbar appears in the bottom of the PCB window Choose connect to Power PCB icon Choose properties icon from the toolbar and the OLE Power PCB connection dialog box appears Choose Parts Filter to enable only component selection Select move icon from the Design toolbar and place all the components

RoutingRouting is to lay physical wire connections between pins. For double sided design we can have our traces laid on both top and bottom layer of the board. On the toolbar we can see a dropdown list which allows us to switch from top to bottom layers.Another way is to use modeless command by hitting I from the keyboardDynamic Route Editor (DRE)

Choose preferences icon Select design tab in the on-line DRC box check prevent error Select diagonal for line/trace angle Select design icon from the toolbar Click on the route icon in the toolbox

CAM (Computer Aided Manufacturing)In this section we will generate the CAM documents Choose files >> CAM Click add button In the document name type “Routing, Bottom” Select routing from the document type drop down list Select bottom and click ok Select preview to see how the artwork appears as a photoplot Choose close to exit the preview window Choose save to save the CAM document

Document name Document type Output file Layer Selection Items on PrimaryRouting, Bottom Routing Art002.pho Bottom Pads,traces,lines,

vias,copper,textSilkscreen, top Silk screen Sst001.pho Top

Silkscreen topRef des, outlinesText, outlines

Solder maskBottom

Solder mask Sm002.pho BottomSolder mask bottom

Pads, test pointsLines, copper , text, test points

Drill data NC Drill Drl001.drl N.A

Routing, top Routing Art001.pho Top Pads, traces, lines, vias, copper, text

Solder Mask, top Solder mask Sm001.pho TopSolder mask

Pads, test pointsLines, copper, text test points

Run to Generate CAM output files Return to define CAM Document dialog box. Highlight all documents in document name edit box Click run button, and answer yes in response to the prompt. This will output all CAM files

Post Lab Question:11. Name four common components that belong to the through hole technology.12. What is Bill of Material (BOM)?13. What is a solder mask layer?14. In schematic capture, there are ways in which 2 or more pins can be connected together. Describe

two ways to accomplish it.15. After you have imported the net list into the Power PCB environment, what are the steps you should

do prior to component placement?

Result:We have learnt how to create a Routing and CAM files with Power logic and export the design to Power PCB for PCB layout.

EXPERIMENT 4 Date:CREATION OF PCB BOARD OUTLINE

OBJECTIVES: To create a schematic with Power Logic To create a design for PCB lat using Power PCB To use copper pour to create Power and GND planes

HARDWARE/SOFTWARE REQUIRED: Computer with following configuration P4 processor, 160gb Hard-disk, 1gb of RAM Power Logic and Power PCB installed in the computer

PROCEDUREPART I – Schematic Capture

With the help of the parts list draw the schematic and save r schematic as excerciseB.schIn r schematic make sure that:

The component values are correctly entered. The pin numbers for all the resistors are not displayed Reference designators are all in upright position. Generate the net list and name it excerciseB.asc

PART II – PCB Lat Set display origin at the bottom-left corner of the board Import net-list Set all design rules as shown in table below and set preferences before proceeding to the next

step.Trace Width

Net Name Minimum Recommended Maximum All ClearanceDefault 10 12 15 12+5V 20 20 50 20GND 20 20 50 20

Disperse the components. Place the remaining components at r own discretion. Place them logically. Don’t forget to do length minimization.

PART III – Power/GND Planes and Copper PourIn order to reduce noise in a design, copper planes are very often added to PCB. Other than to reduce noise in the power and ground supply, copper pour can also be used for thermal(heat) dissipation.The main steps to add copper pour planes to typical 2 layer board are:

Route the +5V signal trace on the top layer – identify the +5V net and route all the +5V connections in the top layer. Use “Highlight” to find all the i-5v nets.

Route the GND signal trace on the bottom layer – Identify the GND net. Route all the GND connections in the bottom layer. Use “highlight” to find all the GND nets.

Route all the other connections – the other signal lines can be routed either on the top or bottom layers.

Create the GND copper pour outline and flood the bottom layer. Do the same for the top +5V plane.

Post Lab Question:

1. List all the CAM files that you need to provide your PCB manufacturer if you want to fabricate a double-sided PCB board, with components mounted only on the top side.

2. On completing the PCB placement and routing, what are the 2 design checks that you should perform for the entire board?

3. What data is found in the net-list?. What is the purpose of creating the net-list in Power Logic?4. What is the main advantage of using Dynamic Route over Manual Route? Before Dynamic Route

can be used, an option in the Design -> Preferences must be enabled. What is it?5. Should we set the design rules before or after component placement? Justify your answer.

RESULTHence the creation of PCB board outline is completed successfully

EXPERIMENT 5 DATE:ROUTING

OBJECTIVERouting is to lay physical wire(traces) connection between pins. For double-sided design, we can have our traces laid on both Top and Bottom layer of the board.HARDWARE / SOFTWARE REQUIRED:

Computer with following configuration P4 processor, 160gb Hard-disk, 1gb of RAM Power Logic and Power PCB installed in the computer

PROCEDUREChanging layersLayer(s) can be specified either top or bottom routing.On the tools bar, drop down list box

This allows to route the bottom layer. From the keyboard hit “I” for bottom and for top layer “Ii” CHANGE GRID SIZEBefore route, set Design grid to 10 and Display grid to 50 for both X and V. If are not able to see the grids, press ”page up” or “page down” to either Zoom IN or Zoom OUT.Prior to routing, select tools >> Length Minimization to optimize the trace length while routing the design.Note: for through hole boards, start routing on the bottom layerDynamic Route Editor (DRE)

Choose preferences icon Select design tab in the on-line DRC box check prevent error Select diagonal for line/trace angle Select design icon from the toolbar Click on the route icon in the toolbox

Deleting Routes Click on the right – mouse button. Choose select anything from the pop-up menu. Select the segment of a completed/unwanted route and press the delete key. Choose the undo icon from the toolbar to undo the deletion. Verifying r design – perform clearance/Conductivity check

When the board is fully routed, use the verify Design to check for clearance and connectivity errors. Select tools >> Verify Design. The verify design dialog box appears. Select clearance radio

button. Then press the start button. If there is a design violation, an error message will be appear in the location edit box. If the clearance check is ok, go to verify design dialog box again, and check the connectivity

radio button, and start the check. Make sure that there are no errors. POST LAB QUESTION:

6. Explain the difference between design grid and display grid in Power PCB.7. What is the purpose of Bill of Material (BOM)? List 4 items usually included in the BOM.8. The dimensions of a rectangular PCB board are 3000 mils by 2000 mils. Give the dimension of

the board in millimeters.9. If possible, we try to route a PCB on just one layer instead of 2. Why?10. Fill in the blanks below showing the PCB Design flow.

RESULTHence the routing is done successfully.

EXPERIMENT 6 DATE:GENERATION OF CAM FILES

OBJECTIVEIn this session, generation of the Gerber files and Excel on (aka NC Drill) files required for the production of the PCB Boards will be done.HARDWARE/SOFTWARE REQUIRED:

Computer with following configuration P4 processor, 160gb Hard-disk, 1gb of RAM Power Logic and Power PCB installed in the computer

Creating CAM (Computer Aided Manufacture) documents:- Choose Files>>CAM. The Define CAM Document dialog box appears. Click Add button. The Add Document dialog appears. In the Document Name text box, type “Routing, Bottom”.

Select Routing from the Document Type drop down list. The layer Association dialog box appears.

Select Bottom and click OK Select Layers from the Customize Document area. The Select Items dialog box appears. Select Board Outline from the other area. Choose Preview to and see how the artwork appears as a photo plot. Choose Board from the Zoom area of the Preview window to fit the layer image to the view. Choose Close to exit the Preview window. Choose OK to close all dialog boxes and return to Define Cam Document dialog box. Choose Save the CAM Document which is just created.

We have created a CAM file whose document name is “Routing, Bottom” and output to “arto2.pho”. Now set up the remaining CAM files as shown in the table.a double-sided board, we need to produce the 2 additional artwork.

Document name

Document type

Output file Layer Selection

Items on Primary

Routing, Bottom

Routing Art002.pho Bottom Pads,traces,lines,vias,copper,text

Silkscreen, top Silk screen Sst001.pho TopSilkscreen top

Ref des, outlinesText, outlines

SoldermaskBottom

Solder mask Sm002.pho BottomSoldermask bottom

Pads, test pointsLines, copper , text, test points

Drill data NC Drill Drl001.drl N.ARouting, top Routing Art001.pho Top Pads, traces, lines, vias, copper,

textSolderMask, top

Soldermask Sm001.pho TopSoldermask

Pads, test pointsLines, copper, text test points

Ensure Top Mounted is selected for Silkscreen layer.Preview ALL ARTWORK files:-

Default artwork should look like those given in the Appendix. To see all the layers in the Preview Window, choose SETUP and make “visible” all the

documents that should be visible.Correcting Misalignment/Displacements:-In the event that the preview documents are not aligned properly, we can still EDIT each of the documents. Select OPTIONS. Check that the offset and scaling are the same for every document.Then check the Device Setup for the Photo plotter. Choose the Advanced button and ensure that the data format is the same.Likewise, check the Customize Document>> Options and Device Setup for the Drill Data file:Take special note of the data format used for the *.drl file:eg:2 leading and 3 trailing digits, trailing zeros suppressed, English Units and Excellon format.Preview all documents again. Make sure that all the artwork are properly aligned.RUN to Generate CAM output files:-To generate and save all CAM files,

Return to Define CAM Document dialog box.Highlight all documents in Document Name edit box.

Click Run button, and answer Yes in response to the prompt. This will output all CAM files (artwork and its aperture table) to the z:CAM folder in Default home directory. Check CAM folder to verify that the files are there.Zip/Compress Artwork into a file. Leave the compressed file in z:\CAM\default directory.

Post Processing:-Dimension the board outline.Generate the BOMGenerate the following CAM files:

(i) Routing Top, (ii) Routing Bottom, (iii) Silkscreen TopUsing GC-Prevue (Graphics code Gerber Viewer), import CAM files into the software to view. Make sure that all artworks are all neat and tidy. Print-outs of the above are not required.Artwork for Exercise A- Logic Probe:-

The following diagrams are Dimensions of Board outline, Routing Bottom, Silk Screen Top, Solder Mask and NC List.

POST LAB QUESTION:11. What do “DIP” and “SMD” stand for?12. (i) What is a CAE decal? Where is it used or found?

(ii) What is a PCB decal? Where is it used or found?13. What is a solder mask? What is the purpose of the solder mask?14. Explain “Forward Annotation” and “Backward Annotation”.15. There is a gap (or space) of 50 mils between 2 pads on the PCB. If the clearance rule for trace to

pad spacing is 10mils. What is the maximum width of the trace that can pass between the pads. If necessary, draw on the space below to illustrate your answer.

16. What is the purpose of Bill of Material (BOM)? List 4 fields of information that you will include in the BOM.

17. You have entered the capacitance value for a capacitor using the “query” option. But, the capacitance value does not appear on the schematic. What could be the possible reason?

18. A common unit of measure in PCB design is the “mils”. How much is 100 mils in millimetres? What is 500 mils in millimetres?

19. The pin pitch for a Dual-Inline Package IC is 100mils. Suppose the radius of each pad for the IC leg is 30mils.

(i) What is the clearance (space/gap) between the 2 pads of the IC?(ii) Can a trace of 20mils go in-between the pads if the design rule specifies trace-to-pad

clearance of 15 mils? Why?Result:Hence the generations of CAM files are successfully created.

EXPERIMENT NO:7PART CREATION

NEW CAE DECAL WITH EXISTING PCB DECALOBJECTIVE:1. To understand the need for part type creation.2. To understand what constitutes a part type.3. To learn how to create the CAE decal for the part type using the CAE decal wizard in power logic.4. To learn how to assign multiple gates to a single part.HARDWARE/SOFTWARE REQUIRED:

Computer with following configuration P4 processor, 160gb Hard-disk, 1gb of RAM Power Logic and Power PCB installed in the computer

Part 1- Understanding Part Type

The following example shows some typical entries in a net list.

For resistor R1, RES-1/8W is the part name and R1/8W is the name of the PCB decal. Similarly, for the part U1, NE555 is the part name and DIP8 is the PCB decal name.

What is a Part Type?A part type comprises of the following:1. A CAE decal or logic symbol (eg. Figure la)2. A PCB decal or footprint (eg. Figure 1 b)3. Electrical parameters (such as number of pins, signal pins, family name, assignment of pins, etc.)

An example of a PADS part type is a 7404 (as in figure 1)Part type name: 7404CAE decal: INVPCB decal: DIPI4Electrical parameters: Six logical gates (A through F) using 12 of the 14 pins with one power pin and one ground pin.You can create a part type in Power Logic or in Power PCB;But, you can create a CAE decal only in Power Logjç, and create a PCB decal only inPower PCB.

PART 2 - Creating a New Part TypeIn this exercise you are going to create a new library part type, an IC, known as P1C18F4550

Enter the Part Editor by choosing Tools>)’Part Editor1. Invoke Power Logic3. Within the Part Editor, choose File>*New.4. Choose Part Type in the Select type of editing item dialog box, and then chooseOK.

5.From the icon toolbar select edit Gate icon 6. Click Ok to warning.Creating CAE Decals with the CAE Decal Wizard

1. Choose the Drafting icon from the toolbar to open the Drafting toolbox.

2. Choose the CAE Decal Wizard from the Drafting toolbox.3. In the Box Parameters area, type 800 in the Mm Box Width text box.4. Type 20 in the Pin Count text box for the Left Pins and Right Pins.5. Set the Pin Count for Upper Pins and Lower Pins to 06. Choose OK to create the CAE Decal.Adding New TerminalsYou may also add pins manually and modify symbols on the pins also.

1. Choose the Terminal Toolbox icon t11Ii from the toolbar. The Terminal toolbox appears.

2. Choose the Add Terminal icon from the Terminal toolbox.3. Choose the PIN decal from the Pins list box, and choose OK.4. With the new terminal attached to the cursor, you may Rotate or Mirror the terminal.5. Position the terminal and click to place the terminal, if necessaryModifying the PIN TerminalsTo change any property of the pins, select the pins and do a Query. A dialogue box will appear and you will be able to change the PIN Decal, PIN Number, PIN Names and other properties of the PIN.Assign names to all the pins.

Number icon, can be used to assign pin numbers to the terminals. Click icon, then the ?t pin. Assign it pin number Set Pin on theSaving the Part TypeTo save the part type, choose the save as option in the File menu. Navigate to the z:Iib\mylib library, and type P1C18F455O in the Name of Part and MY_PIC in the Name of Gate Decals text box as shown in the figure . Choose OKAdding Electrical Information and Assigning PCB DecalA part type would be complete only if it hasA CAE decal,A PCB decal andElectrical information.As of now, for the part P1C18F4550, only the CAE decal has been created and assigned. We still need to add electrical information and assign the PCB decal. 1. Within the part editor, choose the Edit Electrical icon from the toolbar.

1. The Part Information dialog box appears.2. Choose the General tab.3. In the Logic Family area, select CMO to assign it as the family type for the part type.This also assigns a default reference designator prefix of U (Observe below the LogicFamily Box). Type U in the Prefix List Box.4. Choose the PCB Decals tab.5. Select the All Libraries in the Library list box.6. Set the Filter to DIP*, type 40 in the Pin Count text box, and choose Apply.7. Select the DIP4O-600 PCB decal, and choose Assign New to assign the PCB decalas the first (and only) PCB decal for the part type.

8. Choose the Gates tab,The pins and their names will be listed. Although the PIN Types should be specified,we shall ignore them this time.

Add User-defined AttributesFinally, you will add user-defined part type attributes.1. Choose the Attributes tab, and then choose Add.2. Choose Browse Lib Attr. The Browse Library Attributes dialog box appears.3. Select Description and choose OK.4. Press Tab to switch to the Value cell and type P1C18F455O5. Choose Browse Lib Attr. again and repeat the previous steps to add the following attributes and values.Add User-defined AttributesFinally, you will add user-defined part type attributes.1. Choose the Attributes tab, and then choose Add.2. Choose Browse Lib Attr. The Browse Library Attributes dialog box appears.3. Select Description and choose OK.4. Press Tab to switch to the Value cell and type P1C18F455O5. Choose Browse Lib Attr. again and repeat the previous steps to add the following attributes and values

6. When you have entered all the attributes, choose OK to complete the entry of the electrical parameters for the part type.

Save the Part TypeChoose File>”Exit Part Editor1. Then choose Yes to save the part.

2. You are now out of the part editor and back to the schematic drawing window.

Test the Part Type CreationChange the schematic sheet size to A4.Try calling the part you have just created by adding the new part to the schematic 1. Choose add part icon from the design menu.2. Select the part you created by typing MYRE* in the part name list box and place a few instances of the part on your schematic. If you have problems in adding the part, check your part creation.3. Save the file as, say, Exercise C.Sch.4. Generate the net list and exit Power logic.5. Invoke Power PCB.6. Import the net list you created.7. Disperse the components using the disperse components option in the Tools pull- down menu.8. Check whether the PCB decals that appear on the Power PCB editor correspond to the part you created.9. Save the file as ExerciseC.pcb and exit.You have completed the P1C18F4550 part type

Assign PCB decal and Add Electrical Parameters1. Click OK. Choose Edit Electrical (or click Edit Electrical icon). Just a minute! Recall.This Electrical menu item is used to assign CAE Decal to PCB Decal to form Part Type. You have used it before in creating IVIYRE32KB.2. From Logic Family list, select TTL.PART 3 - Creating a Part Type with multiple gatesSuppose you need to design a Part Type for 74LS86 (XOR gate IC). You could have followed the procedures in PART 1 and use a DIP 14 PCB Decal to form a Part Type CAE Decal. (Note: Do not draw this decal. Read on...)TASKYou will draw just 1 XOR gate(CAE Decal), that then assign it 4 times to the DIP14 PCB DecalCreating a new part with multiple pates1. Launch Power Logic application.2. Enter the Part Editor by choosing Tools Part Editor.3. Within the Part Editor, choose File/New.4. Choose Part Type in the Select type of editing item dialog box, and then choose OK.

5. From the icon toolbar select edit Gate icon6. Click Ok to warning.7. Select Drafting toolbox.8. Click Create 2D Line icon

RESULTS:the need for part type creation, constitutes a part type, was understood and Learned to create the CAE decal for the part type using the CAE decal wizard in power logic. Also learned how to assign multiple gates to a single part.

EXPERIMENT NO: 8

CREATING NEW CAE DECAL AND NEW PCB DECAL

OBJECTIVES:• To learn how to create a part with new CAE and PCB decals.

• To learn how to create a connector part

HARDWARE/SOFTWARE REQUIRED: Computer with following configuration P4 processor, 160gb Hard-disk, 1gb of RAM Power Logic and Power PCB installed in the computer

PART I - TRANSFORMER PART CREATIONYou are given a transformer with the following electrical and mechanical specifications (Dimensions in Figure 1A and 18 are in Inches).

The Basic Steps are as follows:Step 1: Create the PCB Decal in the Power PCB Decal editorStep 2: Create the CAE Decal in the Power Logic Part editorStep 3: While still in PowerLogic Part editor, assign the PCB decal created in Step 1 using Edit>>Electrical.

Creating PCB DecalStart Power PCB. Select the best units for drawing the footprint and placing the terminals (eg. use metric if the dimensions are given in millimeters).1. Select Setup>>Preferences2. Choose tab Global>>Design unit select mil (Hint:1 inch = l000mil)3. Choose tab Grid>”Set Design Grid to 50 and Display Grids to 100.

4.From the Main Menu, Choose Tools>>Decal EditorOnce you enter the Decal Editor, text labels and a PCB decal origin marker appear.

The NAME text label is a placeholder for the reference designator of the part. The TYPE text label is a placeholder for the part type name of the part.

The origin marker identifies the origin of the part, which is used when you move or rotate thepart.5. At Drafting toolbox select 2D Line icon.6. Use 2D Line to draw the physical outline (Fig. I B) of the transformer on the Top layer.7. To add terminal, use the Terminal icon.8. If the numbering sequence of your pins is different from Figure 1 B, select the pointer iconselect the 1St pin and then do a right-mouse-click. Select Renumber Terminals from the box shown below.9. Double click on left mouse button to complete

Reposition the Terminal NumbersRight mouse click, select Terminal Name /Number.Select the terminal number to be moved and right-click mouse. Choose Move option and move the number to the desired location.

Save Decal as MyTxfDecal in the library z:libmylibExit Decal Editor and then exit Power PCB application (Click No to the Create New Part prompt that appears. We are not going to create the part type lust yet.)

Step 2 Creating CAE DecalCAE decal can be created only in Power Logic. We shall now create the new part and new CAE here, just like we had done before.Launch Power Logic application and go to the Part Editor.Choose File>>New’*Part Type, OK.then Edit>>Gate. Click OK to the warning,Create the CAE Decal given in Figure. The Display Grid is set at 200mils and the DesignGrid at 5OmiIs. Make use of Figure to work out the dimensions of the CAE decal. Note: Use 2D line to draw this figure and then add pins to itFile>>Return to Part. Click Yes to keep changes to the Gate.Save your work and then go on to “Edit Electrical”

Step 3 Part Type: Assign PCB Decal and add Electrical parametersGoto Edit>Electrical.Enter the following information in the respective property tab:Select the General Tab and pick ANN’ for Logic Family

Next select the PCB Decal Tab and Assign “MyTxf Decal” to the PartSelect OK to exit the Part Information for Part Dialog box.Save Part Type as MYTXF in the library mylib.Click OK and then exit Part Editor.You have completed the PART 1 OF EXERCISE 0. Now test the part you created, make sure that your new part can appear in both PowerLogic and PowerPCB.You can save your files as ExerciseD.sch and ExerciseD.pcb in PowerLogic and PowerPCB respectively.

PART 2- CONNECTOR PART CREATIONThe objective of this exercise isto create a connector (MY16PINCON) using the Library Manager and PCB Decal Editor.For this connector (MYI6PINCON), you will be using an existing CAE decal and hence you need to create only the PCB Decal.

The steps are as follows:Step 1: Create the PCB Decal in the PowerPCB Decal editor.Step 2: Assign the existing CAE decals from the library to the PCB decal created and then acid electrical parameters.

Step I : Creating PCB Decal for ConnectorCreate a PCB decal for the 16 pin connector shown below. The spacing between Terminal I and Terminal 3 is lOOmils. Spacing between the 2 rows of terminals is 50 mils. Terminal I is lOOmils from the vertical edge of the box and 50 mils from the horizontal edge of the box.

Adding TerminalsLaunch PowerPCB.1. Choose Tools>>Decal Editor to enter the Decal Editor.2. set the design grid to 50 by typing g50 and pressing Enter.

3. Choose the Drafting icon from the toolbar.

4. Choose the Terminal icon from the Drafting toolbox.(You are now in add terminal mode. Each click of the left mouse button will add a new terminal at the location of the click.)5. Move the cursor over the decal origin marker and click to add the first terminal at the decal origin.6. Move the cursor to location X50Y50 (using the X,Y location display on the Status Bar as a guide) and click to add the second terminal. Each terminal is sequentially numbered as it is added to the decal. The terminal number is also the pin number. For example, terminal 1 is pin number 1, terminal 2 is pin number 2 and etc.

Assigning Pad Shape and SizeThe next step is to assign pad shape and size. This is performed in the pad stack editor.1. Select one or a group of pads and then does a right-mouse click. Select “Pad2. You can change the shape and size of the pads and the diameter of the holes as well.3. In the Parameters area, change the diameter of the pad to 55. At the bottom of the dialog box, change Drill Size to 28 (mils).4. Choose OK to close the pad stack editor and apply the changes.

You create part outlines with the 2D line drawing tool.

1. Choose the 2D Line icon from the Drafting toolbox.2. Click the right mouse button and choose Rectangle from the pop-up menu.3. Draw the box to enclose the terminals.Creating a Component Outline4. Move the “Name’ and “Type” and place them outside the box.

Save the PCB DecalYou have created your PCB decal in Power PCB. To save the decal to the library:1. Choose the Save icon from the toolbar.2. Save the PCB Decal to your personal folder, ie z:\lib\mylib3. Type the name MYI6PINCON in the Name of PCB Decal text box. Click OK4. Choose No to abort the automatic creation of a new part type. The manual creation of a part type for the connector is covered in the next section.5. Go to File>>Exit Decal Editor. Exit Power PCB.

Step 2 : Creating a New Part TypeYou will now create a part type for the new 16 pins connector using the Power logic Part Editor.

1. In Power Logic, go to Tools>>Part Editor and do a File>>New.2. . Select “Connector” and click OK.

3. Select “Edit Electrical” icon.4. You will see the above window with the “Connector” tab turned on.5. In the Logic Family list box, scroll and choose the CON family type, which establishes the default reference designator prefix J for this part type. Type 16 for pin count

Assign a PCB Decal1. Choose the PCB Decals tab.2. Choose the All Libraries library from the Library drop-down list box.3. Type MY* in the Filter text box and choose Apply.4. Select your MYI6PINCON decal from the Unassigned Decals list box.5. Choose Assign to move the decal into the Assigned Decals list box

Assign CAE DecalsNow assign CAE decals for the part type.1. Choose the Connector tab.2. Choose Add. Choose Browse from the Special Symbol cefl. The Browse for SpecialSymbols dialog box appears.3. Choose the “EXTIN” symbol from the All Libraries library, and choose OK.. Double-click in the Pin Type cell field on the Connector tab.5. Choose Source from the list box to assign input pins as sources.6. Choose Add again, and choose Browse from the newly added Special Symbol cell. The Browse for Special Symbols dialog box appears.7. Choose the ‘EXTOUT” symbol from the All libraries, and choose OK.8. Double-click in the Pin Type cell on the Connector tab.9. Choose Load from the list box.Add Part Type AttributesFinally add the following attributes to the connector:

Save the Part TypeNow that the part type definition is complete, save the new part type.1. Choose OK. The Save Part Type to Library dialog box appears. Navigate to your home directory library; for eg. z:\lib\mylib2. Save the part type as MYI6PINCON. Select OK.3. Confirm any messages that appear asking if you want to overwrite the file.4. Exit Decal Editor.You have completed the PART 2 OF EXERCISE D. Now test the part you created to see if it can appear in the schematic and ported to the PowerPCB.

RESULTS:we learnt1. To create both a CAE decal and a PCB decal and use them to create a new part type.2. To create a connector PCB Decal and use an existing CAE decal from the library, to form a new Connector part type.