1. Part II: Using PCB Layout Software – Custom Component Libraries
Introduction to Prototyping a LED Driver
Part II: Using PCB Layout Software – Custom Component Libraries
September 24-28, 2012 Carol Lenk

2. What’s in a Component Component Board Symbol Schematic Symbol
Connection between pins and pads
Values, Component height, Digikey/Mfr part number
Board Symbol
Pad Footprint: copper, mask
Reference Name
Silkscreen, Document
Schematic Symbol
Schematic Shape
Pins

3. HV9910 Component not in library. Package is standard.
Schematic symbol is standard.
Need to make a new Component that uses existing SO-8 PCB symbol and schematic symbol.

4. Find SO-8 PCB Symbol Library Manager PCB Symbol Tab Use All Libraries
Search for “SO” and 8 pads
Click on 8-SOIC [prolib]

5. Find SO-8 Schematic Symbol
Library Manager
Schematic Symbol Tab
Use All Libraries
Find…
Search for “SO” and 8 pads
Click on FCH-SO8 [fairchild1]

6. New Component
Library Manager
Components Tab
New Item…

7. HV9910 Assign pins 1 to 1 Enter Terminal Name
Save to our custom library

8. Custom Footprint Download datasheet from Digikey.
Find component size and recommended land pattern.

9. Custom PCB Symbol Create custom PCB Symbol library Library Manger
PCB Symbols Tab: New Lib… : 9910Demo.psl
Copy a 2 pad footprint
In prolib.psl, copy SMD1 to custom library
Name new pcb symbol DR1050

10. Edit Custom PCB Symbol
Library Manager, go to 9910Demo.psl, select DR1050, click Edit
Right click on S (symbol origin) : Origins : Set System Origin at Item
Menu: Units: mm
Double click on pad to bring up Properties
Change position (center of pad)
0.8
4.45
4.45
3.65 X

11. Menu: Settings: Grids: Step Size 0.1mm.
Double click on corners to add chamfer.
Move R reference locator to outside of body
Pads underneath part makes it hard to hand solder.
Increase pad size by 1 mm.

12. Library Manager: Component Tab: New Item
Component Editor
Connect Sch Terminals to PCB Pads
Save to custom library
Add Component to schematic.

13. MOSFET

14. MOSFET
Add pad numbers
Add description in Properties window.

15. Diode Schematic Symbol Need to create custom PCB symbol
Use Diode-2 in diode.ssl library
Need to create custom PCB symbol
Copy pcb symbol “1206” from sm.psl library.
Name new symbol “SMA”

16. Diode PCB Symbol With line selected, hit “L” to change layers.
Purple items are on Top Document layer to show components. Layer not printed on PCB.
Yellow items are on Top Silkscreen layer. They are printed on the PCB.
With line selected, hit “s” to change line style thickness.
For closed shape, use Properties and click on Filled.

17. Footprint Guidelines Reduce production errors. IPC Standards.
Alignment, solderability, inspectable.
IPC Standards.
From datasheets for resistors, capacitors, etc.
Generally ~ 0.005” wider overall, 0.020” longer on each side.
Hand solderable for prototypes.
AVX Technical Information: Solder Pad Geometry Studies for Surface Mount of Chip Capacitors.

19. How is a PCB Made? 2 1 3 4

20. Looking at a PCB White Silkscreen Pin connector
Reference Designator on Silkscreen Layer
Green Solder Mask
Copper Trace visible under solder mask
Tinned Pad

21. Layers In Interaction Bar (Menu: View or F9), Layers Tab is at bottom.
Hit “c” to bring up colors.

22. Thank You