This example demonstrates how to create a layout footprint for an 0805 capacitor in the Footprint editor. The figure below shows the dimensions of a standard 0805 capacitor footprint:
You can create the above example as follows:
To create a footprint:
Click Tools on the Genesys menu and select New Footprint from the Footprint Editor menu.
Double-click in the Footprint editor to open the Layout Footprint Editor Properties window.
Click the General tab.
Select mil from the Units list.
To place the first pad:
Click the Pad button ( ) on the Layout toolbar, and then click in the Footprint editor.
Click the Square/Rect button in the Pad Properties window.
Type 33 in the Pad Width box.
Type 40.6 in the Pad Height box.
Select Metal from the Layer list to place the pad on metal.
Type 0, 0 in the Location boxes to place the pad center at the origin.
To place the second pad:
Repeat steps 1-5 above.
Type 48.3, 0 in the Location boxes as the second pad location. This sets the center-to-center pad spacing to 48.3 mils as shown in the figure.
To draw the silk screen:
Click the Line button ( ) on the Layout toolbar.
Draw a line in the Footprint editor, and then double-click the line.
(mils) in the Line Width box.
Note: To prevent silk screen interference with metal layer objects, all silk is kept at least 10 mils from the nearest metal.
Click the Rounded Ends check box to change the line shape to round.
Select Top Silk from the Layer list to place the line on the top silk layer.
Type -31.5, 35.5 in the Start boxes.
-35.3 in the End boxes.
Note: The Start and End figures include 10 mils beyond the pad width plus 5 mils for half the silk line width.
Press the O key to create a 90-degree line.
This figure shows a silk line before pressing the O key:
This figure shows a silk line after pressing the O key:
Draw another rounded line on silk from -31.5, 35.3 to 79.8, -35.3.
Press the O key to create another angle, and then press the F key to flip the angle. This creates a box around the pads with a 10 mil clearance.
To place the designator text:
Click the Text button ( ) on the Layout toolbar.
Click in the Footprint editor to open the Text Properties window.
Type @DES in the Text box. This allows the schematic element using this footprint to fill in the element designator on the layout.
Select Top Silk from the Layer list.
Click the Use Default Size check box to allow text sizing later when the footprint is used in a layout.
Type 24.15, 50.3 in the Location boxes. This centers the text horizontally and allows a 10 mil vertical clearance for the silk screen box.
Click the Center X button for X-justification. This forces the text to always center horizontally and keeps the 10 mil clearance from the part box.
Click the Bottom button for Y-justification. Any other Y-justification allows the text to expand downward with increasing size, breaking the 10 mil separation rule.
To place footprint ports:
Click Layout on the Genesys menu and select Place Footprint Port.
Click the center of the first pad to place a footprint port on that pad. The Port Properties window appears.
Type 25 in the Draw Size box.
Repeat steps 1-4 to
place a footprint port on the second pad.
Note: Be sure to place footprint ports on the same metal layer as the pad.
The final footprint is shown below: