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Very first steps with Cadence PCB Editor/Design Entry HDL

First Layout

Hello,

 I'm starting with my first layout (master thesis: rf frontend) in Cadence SPB 15.7 and have a lot of questions. Here are some of them:

 1.) Before I start with the schematic, I think I have to create the schematic-symbols and the footprints of the ICs. I already followed a tutorial which showed how to make the padstacks and the footprints with assembly outline, silkscreen outline, package boundary. I startet with an easy footprint of the MAX4447 with SOIC 16 pins. But I have no tutorial which explains how to create the schematic-symbol and how to link it with my new footprint. Any idea where to find one?

2.)  The next parts, I have to create are TSSOP20, SOT-89, QFN-LP3, 20pin MCM, 56TQFN, SOT3, SOT-666, QFN-6.

It's a lot of work and I don't know if everything I do is correct. So are there downloadable footprint packages which contain some of my needed footprints? I think I have to compare every downloaded footprint with the datasheet of the part but it would speed up my work a lot.

3.) Any other hints? =)

 regards,

First_Layout

 

  • S Grant Davies

    Hi Yes you will first need to have the schematic part "symbols" ready to be placed onto your schematic, and once you have a working schematic each part "symbol" will need to be assigned a "PCB Footprint", that way when you ECO (engineering change order) from your schematic into allegro, Allegro knows which footprints to call upon to bring into your layout design. so you do need schematic symbols and pcb footprints, before a layout and be proceeded with.   yes 15.7 is a little old hat, I use 16.01 (even though there is 16.2 currently available) 16.3 is coming out very soon also. good luck on your design. Stephen Grant-Davies - QuantumCad.

  • pondicherry
    hi iam also learning allegro.Do u have any material to study abt.
  • HANUMAGOUDA
    Hi khurram, My self Hanumagouda Patil from India, i am new to to the allegro.Can you please tell me how to create footprint in allegro and how to use those footprints for my design. I am using Cadence OrCAD v16.2 &16.3. I hope 'll get a complete procedure. please reply to my mail id: hani.gmit@gmail.com Regards, Hanumagouda Patil
  • S Grant Davies

    hiya,

    (1) first and foremost, you should realise when you install Cadence Allegro, it will install footprint libaries for you these can be viewed and used from

    C:\Cadence\SPB_16.3\share\pcb\pcb_lib\symbols

    you just need to open them (*.dra) ( its probably worth opening some up and experimenting here to get an idea)

    eg cap300.dra ( you also might notice for every *.dra file there is also a psm this is normal and Allegro needs both of these for its ECO process.

    (2) every part on your schematic needs an allocated footprint eg (cap300) you dont need to add in the .dra

    once this is complete you also need to make sure in setup user preferances, Paths are set up correctly either for using cadence default lib or in case you want to use your own.  alternatively to that, you can just place your  *dra and *.psm files in the exact same folder as your intended  .brd   this way you dont need to configure paths (your choice)

    (3) you should now be able to take your schematic into Allegro, oviously you might encounter isues along the way but thats generally a good starting point. good luck, it is a bit of a learning curve to use Allegro, but once you do, its one of the best PCB CAD tools on the market.

  • lynsey

     Here is a quick tutorial for the Cadence Allegro Design Entry HDL -

     

    http://www.referencedesigner.com/tutorials/hdl/hdl_01.php

     

     

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