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Footprint property for Allegro

Barca

Hi everyone,

I have used Orcad Capture CIS to design a schematic and I am going to use Allegro PCB designer for the PCB design. Before generating the net list I have to assign a footprint to my schematic symbols in the footprint property field. however I am not sure what is the correct syntax for the allegro footprints.

Where can I find the correct syntax for the allegro footprints in order to fill out my schematic symbol footprint property ?

Barca.

  • redwire
    The footprint goes in the PCB Footprint field in OrCAD.  The name should match the same name as in your library.   There is a library that comes with Allegro but typically the user creates their own symbols.  The symbols/libraries are covered in the Allegro manual.
  • Barca

    Hi redwire,

    Thanks for your answer. In the PCB designer footprint library I have 0603RF_W V_12D and 0805RF_W V_12D. I suppose I have to enter these names in the footprint property fields of my 0603 and 0805 footprint components. Is that correct ?

    Do you know anywhere I could download other footprints for PCB editor ?

    Do you where I could download the footprint maker tool ?

    Thanks again.

    Barca.

  • UlfK

    To answer your first question; Yes - these are the names you should enter.

     In general: I have seen questions like "Where can I find footprints for download" many times. Of course, there are small libraries around on the internet that can be downloaded and used but beware - There are many opinions regarding the pad and courtyard sizes.

     Also keep in mind that the USA and Europe differ when it comes to soldermask vs pad size.

    The best practice is to keep with the IPC7531 suggested standard. For smaller SMD components there are three standards. "Most" "Nominal" and "Least". Most is the biggest and Least the smallest of them. They are chacterized for ie. consumer devices (Most) space is not of an essence, or cell phones (Least) where space is tight and also high frequencies makes the use of small pads necessary.

    There are some tools available that will create footprints automatically. I know of one that can be found on some forums "FootprintMaker", but it was a long time since I saw it. There is also a payed software "LandPattern Wizard" that can create footprints for Allegro, but I have not used it.

    I suggest that you take a look at the IPC standard, then start creating your footprints as your design work goes on. You will quickly learn that there are not that many footprints in a design ,and that many of them (like specialized connectors) requires the knowledge of the Pad Designer as well as the foot print making process within Allegro. I still use the buil-in wizard in order to start the process and then modify the created footprint if necessary.

  • redwire

     Ulfk's response is very good advice.

    There is (was) a freebie tool a while back called "Footprint Maker" that would also do a bunch of parts for you.  I think you had to have a Performance license or better to use.

     

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