Saturday, November 16, 2013

Making CAD files for packages not available in your PCB software

Many PCB software come ready with the basic PCB packages which can be used for routing. But, what if you don't find your package?! I faced the same problem when I was designing for the final year project. Let's see how can you do it easy.

Note: You can use any CAD software for making the footprint of the package(e.g. AutoCAD, I used AutoCAD Electrical 2014, though the generic AutoCAD will do). Also, you can use any software other than Proteus if it supports an "Import .DXF file"option.

Using CAD software is important because some software do not provide you with the precision (e.g. I am using Proteus ARES currently) which can lead to a PCB you wouldn't want. Furthermore, it provides you compatibility, between various design softwares, so, no need to find specific packages, just import the file.

Proteus ARES accepts DXF files for importing package footprints, so this tutorial will aim at creating a .DXF file.

Let's take the STGIPL14K60. Its an IPM released a few months ago by STMicroelectronics, but you won't find a CAD files on their website (some corporations do provide a CAD in maybe another format file e.g. Texas Instruments, if you find one just skip to the last step).

You can see that this package would be a hard nut to crack if you don't know where to find the footprint. But there's this option to your rescue! See the animation and you'll know how. But, for your information, this option can have some other name in other software, so, just try to find out yourself (troublesome eh!).

Well I prefer an animated .GIF (made using so that people craving for bandwidth wont need to download a Youtube video (I understand you guys, I was the same once :-D )

To understand how to make that DXF in any AutoCAD suite, first remember these commands. I think these would be enough for electronic guys, you needn't be speedy or even experts. Try to use a mouse with the keyboard please! We ain't mechanical designers. Just imagine its like drawing in paint, and keep the datasheet of the package with you, that's all.

  • LTSCALE - to change scale to of the whole drawing
  • SCALE - to scale selected objects, needs a base point (a reference to perform the math)
  • D - change dimensional styles if you need them
  • LINE - self explanatory, but you have many good option in AutoCAD to draw a line, e.g. two point, point and slope (just like math equations :) ).
  • POLYLINE - similar to line, but to draw a 2D line with many junctions
  • CIRCLE - To draw our very own CIRCLE!!!!! But you have options here too, e.g. 2-point, 3-point, tangent, etc.
  • MOVE - self explanatory, but needs a base point
  • COPY - self explanatory, but needs a base point
  • RECTANGLE - self explanatory, also has many methods like 2-point and length-breadth
  • MEASUREGEOM - this may be not available in older AutoCAD versions, but you can measure without using DIM category of functions, because you'll have dimension clutter all over the screen (no mess strategy please).
  • ARRAYCLASSIC - to create an array of one object e.g. you can draw 10 lines with same parallel distance by drawing a line and then using this command. Arrangement can be in a rectangular array or a polar array (like chairs around a table).
So, however fancy your package is, however smaller too, use CAD and bingo! You can import it for designing your PCB. 

Now, complete your design, and save it as a .DXF file. I'll just put the image of the complete package, you can refer to the help from AutoCAD for further details.

You can find my .DXF files on this link

P.S. This blog does not endorse any of the companies or software mentioned above. The blog aims to ease a problem which people may face, and can be easily solved using the information provided above. AutoCAD, Texas Instruments, STMicroelectronics, are  trade names, trademarks and/or registered trademarks of the respective owners with which they are associated

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