Introduction to Prototyping
a LED Driver
Part IV: Finishing The Layout – Finishing
Touches and Design Rule Check
September 24-28, 2012
Carol Lenk
Editing Schottky Diode Symbol
• Right click on symbol, select edit symbol in library.
• Save, to our custom library, with same name.
• Make sure in Folder tab, path to our custom library is
at the top.
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Draw diagonal line.
Right click, select Arc: Angle Free.
Copy and paste, hit “r” for rotate.
Save.
• Back in schematic, right click,
select Update Component
Ground
• Schematic symbol only, uncheck PCB Symbol.
• Add to schematic, then right click, Change Net, type
in GND.
Nets
• Every GND symbol must be added to GND net.
• In Interaction Bar on right, select Net in dropdown
box, click on GND to highlight all GND connections.
Through Hole for Input Wires
Schematic
Symbol
Through Hole for Input Wires
PCB
Symbol
New Component
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Library Manger
Component Tab
New Item..
Edit Schematic Symbol
– Caution, leave grid size at 0.025”.
Otherwise, can’t connect wires
to it. (symbol origin and pin (X)
must be multiples of 0.025”
apart.
• Click on Properties, OK to
PCB Symbol
• 22 AWG wire diameter is 0.0250”. Rule of thumb is
make hole 0.010” larger.
• Pad should be 0.014 larger than hole.
– (PCBArtist User Tips Guide p32.
http://www.4pcb.com/book/index.html)
Properties
Add Package
Choosing Package
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Properties
Values Tab
Add.., Value, “V In+”
Double clikc on text,
select display values
LED Terminals
• Add 24 AWG through holes for LE
Update PCB
• Tools: Forward Design Changes.
• Change terminal display
– Double click on text.
– Uncheck Comp Name, check Values.
– Values Tab: check Values.
Add Text
Components on Bottom Layer
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Click on component, hit “f” to flip component to bottom layer.
Move component so that vias are not on the pads.
C1 is flipped to the bottom side.
Select via, hit “s” to change style. Hole size = 15, Width=17,
type in Style=Via1517.
Add Copper Pour
• Click on Add Area for Copper Pour.
• Right click to bring up cursor menu. Segment Mode:
Orthogonal for easy drawing. Double click to finish.
• Hover over Q1 pad to see what net it is on.
• Click on line to select it, Right click, select Pour Copper.
• Select the
same net.
Copper Pour
• Note thermal vias make production easier.
• Power Supplies should have a ground plane on back
side to reduce EMI.
• While drawing copper pour area, hit “L” to change to
bottom layer.
• Select GND net when pouring copper. Uncheck
thermal vias.
Design Rules
• Settings: Design Technology or Shift-T.
• Board to Shape is 20 mils.
• Double click to change. Click on another box
to accept changes. Hitting Return closes the
window without accepting the changes.
Design Rule Check
• Pad to Board and Track to Board should be 0.020”.
Thank You