sexta-feira, 26 de agosto de 2011

Creating land patterns


After making the schematic, several times, we will for the first part of the layout, construction and the use of footprints.
With all connected components, click the main file (.DSN), go on TOOLS, Create Netlist, Select User properties are in milimeters. Should then generate a netlist file with the same name as the schema.
To open the Layout, go on TOOLS, Library Manager, another screen appears, click Add in the Libraries, go to the folder (C:) where Orcad and search is installed in the folder (\Layout_Plus\Library) the file METRIC.LLB.
To make a new footprint for the components in the Library Manager, you must click Create New Footprint, now just add the pads (TOOLS, Padstack) according to data from the datasheet of the component, filling only those fields marked as TOP and add DRILL measure if they are True Hole. To obstacle click (Obstacle Tool) check the format of borders and right click on them, selecting Properties and then selecting Place Outline and Global Layer to make the component format in silk screen is the same, but you must select Detail and SSTOP.









For a com component libraries already known, in time to make the link must seek the most appropriate according to the dimensions in the datasheet. For example a component Dip of 8 legs true hole the corresponding library is DIP100T, and the footprint is the DIP. 100/300/8/w. L.400, W the width and L the length.








Returning to the Layout, go to FILE, New, go to the folder of Orcad on (C:) and search (\Layout_Plus\Data) the file METRIC.TCH then must search the previously generated netlist "Nome.MNL", in the same directory as the schematic.
Most components will find footprint ready, however the MSP, LCD and Switch we should do our own footprints as described in the datasheet of the component.
If the program asks to find a footprint for a component, not cited oil, one should look for some template as the table.





Component
Footprint
LM555
DIP.100/8/W.300/L.425
HT1380
DIP.100/8/W.300/L.400
LM35
TO92
Resistor
AX/RC07
Capacitor
RAD/.300X.125/LS.200/.031
Indutor
DISC/.350X.175/LS.200X.100/.034
Potenciômetro
SIP/TM/L.300/3

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