pcb layout taskkk

8/20/2019 pcb layout taskkk

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Sri Lanka Institute of Information Technology

BEng (Hons) Electronic Engineering

EC 180 Engineering Practice

Laboratory 3 – Layout Design using Orcad

Exercise I :

Part I – Introduction

You are supposed to design the schematic and the PCB Layout for the simple RC low pass

filter that you designed in the previous lab.

When designing the layout, keep in mind that you need to pay attention to where connectors

are needed as when testing the circuit practically, the input is to be given to circuit using the

signal generator and the output should be observed using the oscilloscope (probe).

Note:

Do NOT use the lite version – because routing is not enabled as it is a limited version.

Part II – Schematic Design

1.

Open Orcad Capture

2.

Go to File >> New >> Project

3. In the window that appears select “schematic”

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3.1.Given an appropriate name to the project

3.2. Choose the location

3.3. Click OK

Note: You will be designing the schematic for a

PCB. Therefore, you will be selecting

“Schematic”.

4. Click on Place >> Part

4.1. Click on Add Library

4.2. Click (Ctrl + A) to select all in the “library” folder and click open

5.

In Part (window) : Search for the electronic components required

5.1. To find the resistor search for R and place it on your schematic.

5.2. To find the resistor search for C and place it on your schematic.

6. Search in the section part for “CONN PCB 2” and add TWO of it to your schematic

(Assuming that you would be using the kind of connectors shown to supply

the input and to observe the output when implementing your circuit practically)



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7. Wire your circuit. Now your circuit should look like as shown in the figure below.

8. Double click on each component and find the “PCB footprint column”

8.1. Enter the respective footprint for each of the components with reference to thetable below.

Component PCB Footprint

Capacitor (C1) RAD/.250X.125/LS.200/.031

Resistor (R1) res400

(You have not yet added footprints to the two connectors)

Note: Footprints denote the distance between the pins of a particular component usually

found in the datasheet of the component that you would be using.

9. Go to the Layout design tab in Orcad capture >> Select your design

9.1. Click on Tools >> Create Netlist



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9.2. In the window that appears, go to the “Layout” Tab, ensure the .MNL file is

being created in the location of your project.

9.3.Click OK.

Part III – Layout Design

1. Open Layout Plus

2.

Click File >> New

2.1.In the window that appears : Enter the path given below and click open:

C:\Program Files\Orcad\Layout_Plus\Data

2.2. _DEFAULT.TCH will be found on top of the list. Click on it and select open.

3. Go to the location where you Schematic design was made in Part II.

3.1. Search for the .MNL file that you generated earlier



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3.2.Click open.

4.

The name given to your schematic will automatically appear. Click Save.

5. IF it appears that the footprint “RES400” that we gave for the resistor is unavaila ble.

In such cases:

(Part name appears in the window “Link Footprint to Component” )

5.1.Click on

OTHERWISE : Proceed to step 7.

6. In the window that appears:

6.1. Under Libraries select : TM_AXIAL

6.2.Under footprints search for : AX/.400X.100/.034

6.3. Click OK



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7. We did not add the footprint for the connectors.

7.1.Click on

7.2. Select the library : BCON156T

7.3. Search for the component : BLKCON.156/RH/TM1SQS/W.545/2

7.4. Click OK

8. In Layout Plus: Go to Options >> System settings

8.1. Set Display units to

8.2.Click OK

9. Click on “Tool” >> Dimensions >> Move Datum

9.1.Place the cursor on the convenient location. (This will be now be

the (0,0) point of your board)

10. Follow the following steps to draw the outline of the board:

10.1.

Select >> Tools >> Obstacle >> Select Tool

10.2. Place the cursor on the (0,0) point you fixed earlier



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10.3. Start drawing the outline of the board :

(You may view the distances on the top left hand corner.)

X Length : 60 mm

Y Length : 30 mm

10.4. Once you finish drawing (when you reach the point you started drawing), right

click and select

11. Click Auto >> Place >> Board : This will place all your components within the

outline of the board.

12. Click on the component Tool :

12.1. Arrange the components within the board by rotating them and placing them as

you wish.

(Rotating may be done by selecting the component and pressing “R” and you may

Flip components by selecting the component and pressing “T”)

12.2. Your partially complete layout will be similar to the one in the figure shown

below :



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13. Go to Tool >> Layer >> Select From Spread sheet

13.1. Leave:

Bottom : layer as Routing

GND : Plane

PWR : Plane

13.2.

On the “Layer Type” respective to other layers, double click and select

“unused routing”

14. Click on “Tool” >> Net >> Select From spreadsheet

14.1. Click on the column “width” and set it to;

14.2.

Close the Net window and Click OK.



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15. Click on Tool >> Padstack >> Select from spreadsheet

(You can adjust the size of the points where you solder your components)

15.1.

Close the first window that appears

15.2. As you are routing only on the bottom layer : Set the width and height column

of the Bottom layers to 3

16.

Click on Auto >> Auto Route >> Board.

(You will be able to see the board that has been routed)

17. Click on Options >> Colours

17.1.

Delete all colours other than the ones shown in the figure below

18. Click on Add Text Tool

18.1. Place cursor within the board >> Right Click and Select “New”

18.2. Add the details as given below:

18.3.

Click OK and place the text in the board.



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19. Click on Options >> Colours

19.1. Delete the yellow colour as well

20. Your PCB Layout will now look as shown below:

(You may use zoom all for a clearer view)

21.

Click on File >> Print/Plot

21.1. Setting should be made as shown below

21.2. In the print window that appears select as the printer

and click Print

21.3. Select a suitable location and save your layout as a PCB21.4. Open the PDF File and see whether it has been printed properly.



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Exercise 2 : Layout for DC Motor Driver Circuit

Similarly, Design the layout for the DC Motor Driver Circuit

Exercise 3 : PCB Design

Important Note: Please proceed with exercise 3 of this Lab sheet ONLY on the successful

completion of Laboratory Session 4.

1. Print the PDF File on a transparent sheet

2. Iron the transparent sheet on to a copper board.

3. If any lines are not properly ironed on to the copper board, complete them using a

permanent marker.

4. Put the copper board in to a sufficiently concentrated ferric chloride solution.

5.

Leave the board in the solution for a while You will notice the colour change in the

board turning from the initial colour to pink and then to the colour you expect.

6. Take the board out, wipe and clean the board.

7. Remove the marker lines using “ paint thinner ”

8. Drill holes where pads have been included in the design.

9. Solder the components on to the PCB

10. Test your circuit by giving a suitable input and observe the output.

pcb layout taskkk

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