pcb with orcad

Layout

Power Supply

Nate Moehring

Perspective

OrCAD Capture

OrCAD Layout

Gerber Files

LPKF CircuitCAM

LPKF BoardMaker Pro

Complete Schematic

• Only libraries from the Capture\PSPICE folder can be simulated.

• To find the fuses, switches, and potentiometers, add the discrete library from the Capture folder.

• Document electrolytic capacitor orientation.

• Regulator package TO-220, Regulator library in Capture folder.

Complete Schematic

Export to Layout

• Click on project browser

• With Schematic selected in the browser, select Tools >> Create Netlist from the Menu bar.

Export to Layout• In Layout tab, check “Run ECO to Layout”

Export to Layout

• Start Layout

• File >> New, select “Default.tch” (new project with default attributes)

• Then open the netlist file <projectname>.mnl created by the Capture export we just did.

• Save as Layout project <projectname>.max

Selecting footprints

Axial/.300LX.100W/.031 lead diameter

Selecting footprints

Professional version has more detail

Selecting footprints

• Pots will be mounted on the box, not on the board, so footprint selection is not important. I prefer VRES >> VRES13.

• We are using regulators with the standard form factor of TO-220, mounted vertically.• Professional version has TO-220 library. Vertical

mount is TO-220AB

• If using student version, any 3 leg footprint with proper dimensions will work, such as using a VRES footprint.

Selecting footprints

• Switch, fuse, and LED are mounted on the box, so footprint is not important.

• Other regulators are same form factors, but different pin outs! Double check their traces.

• Modify selections for large capacitors.

• Create footprint for transformer.

Position components on board

• Double check space needed by components (especially heatsinks).

• Double check all pin outs.

• Add vias for input, transformer, and output power connections.

Mounting Holes?

• Plan where you would like to position the PCB and transformer in the project box to determine if it is possible to drill a whole through the PCB at design time (in Layout) so it will easily and securely attach to the box.

• Do this using a large via or custom footprint. (screws will need to be provided by the student)

Tool Tutorial• Every operation has a

different tool in Layout.

• Each tool has different modes.

• To remove a track, select the tool component from the toolbar or menu.

• You must then place the tool into the Select, Add, or Delete mode from the menu or by right clicking.

Tool Tutorial

• You must use the Component tool to move, add, or delete components.

• Use the Measure tool to find the dimensions of your board or a component.

• Must use the <tooltype> tool to move, add, or delete <tooltype>.

Creating a new footprint

• Open the library manager• “Create New Footprint”

• Use Pin tool to add, delete, and move pin connections. • Use text tool to add, delete, and

move text labels.

Connection Points

• Using component tool, select a via to use as an empty whole to connect items off of the board (ie, transformer, fuse, etc…)

• Once placed, must use via tool to move and delete. (Can also use via tool to create, but then it tries to associate the via to a net.)

Capacitor Footprint

• 2200uF, 50V, electrolytic, radial (cylindrical): 16mmx31mm (from datasheet) (lead spacing/lead diameter?)

• 1inch = 1000mils

• 1mil/.001inch * 1inch/2.54cm * 1cm/10mm = 39.37mils/mm

• Xmm = .0254mm * Y mils

• Ymils = Xmm/.0254mm

Capacitor Footprint

Cylinder/Diameter/Lead Spacing/Lead Diameter

Disable Unused Layers

• We’re constructing a single layer board, but CircuitCAM must have top and bottom layers in project.

• Disable layers for Gerber export in Options >> Post Process Settings >> Uncheck “Enable for Post Processing” for all layers except .top and .bot, device as “Extended Gerber”.

• Disable all routing layers except Bottom for trace routing in Tool >> Layer >> Select from Spreadsheet >> Select “Unused Routing” (Drill layer must be enabled)

Global Spacing (for Routing)

Increasing Pad width

• Tool >> Padstack >> Select From Spreadsheet

• Change Bottom and Drill Width for each component’s unique pin style. Make sure to not make pads and holes so big that they overlap!

• Diameter of AWG18 wire is 40mils. Recommend 32mils of copper around whole. Typical padstack size: 72mils

Potential Padstack sizesComponent Bottom Drill

Power cord 200 120

Transformer 150 50

TO-220 Regulators 74 42

Capacitors 74 40

Pots, LED, fuse, switch, 18AWG wires

74 42

1/4W Resistors 66 34

D0-41 Diodes 74 42

These sizes are not guaranteed. It is up to the student to determine the best size holes and pads for their project. It is better to err on the size of too large rather than too small.

Changing trace width(as shared by Nicholas Ange)

• Tool >> Net >> Select From Spreadsheet

• Double click on the Width column header

• Set all values to desired width

AutoRoute Board/DRC

• Make sure overall board size is <= 8in2

• Options >> Global Spacing• Because we’re going to use thick traces (for higher

current), and because this is a simple board and space is not a concern, we’re going to space everything by 32 mils.

• Auto >> Autoroute board/DRC

Changing trace width(post-autoroute method)

• Tool >> Track >> Select Tool

• Place cursor over desired trace, but do not click! Push ‘w’ on the keyboard.

• Select Net, and set width to

32 mils.

• Trace width calculator:http://www.geocities.com/CapeCanaveral/Lab/9643/TraceWidth.htm

Improving Traces• As a general rule:

• Use the Track tool to make changes to an entire net.• Use the Track Segment tool to modify just a single

stretch of a trace.• To draw a new trace, you must first use the Connection Tool

to connect “from here to there”, then click on the connection line using the track or track segment tool to draw the trace. Track tool will do a little more work for you when drawing new traces.

• Avoid:• 90o angles in your traces.• Unnecessarily complex (unintelligent) traces• Keep digital and analog traces separated.

Adding a Border• Tool >> Obstacle >> New

• Draw a shape outlining your board (typically a box). Select the obstacle >> right click >> Properties

• Change the obstacle type to “Free Track” on Bottom layer.

• CircuitCAM will use this to determine where to cut out the board from the rest of the copper. (contour routing)

Adding Text• Write your name on the board using the text tool.

Final Product

Gerber Preferences

Final Gerber Export(as recommended by LPKF)

• Copy ORCAD2CCAM.PPS to your project directory.

• Options >> Post Process Settings

• Right Click >> “Load Post Processing Setup”

• Load ORCAD2CCAM.PPS

• Right Click >> “Run Batch” to generate necessary gerber files.

Final Gerber Export(as recommended by Sara Barnard)

• Double check “Gerber Settings”.

• Setup top and bottom layers for export in “Post Processor Settings”, with device as “Extended Gerber”.

• Auto >> “Run Post Processor”

• Email to me <projectname>.top, <projectname>.bot, and thruhole.tap in <yourname>.zip by 11:59pm Thursday.