How do I build a part on a 45degree angle?

[jreeves]

I need some help, I have to build a Plastronics socket for a BGA. Part number 256BG10B127.

The contact tails sit on a 45 deg angle from the plastic body. How would I go about building this part?

[randychase]

Jenny, do you have a data sheet on this part? It sounds interesting.

[jreeves]

Yes I do have the data sheet. I'm very willing to fax it to anyone you could help me.

I've also call the company to make sure the pads are on a 45 deg angle.

[randychase]

Originally posted by jreeves
Yes I do have the data sheet. I'm very willing to fax it to anyone you could help me.

I've also call the company to make sure the pads are on a 45 deg angle.

Cool.

Fax it to me at 619 583-5607

I will take a look at it. Tom is at IPC in Arizona right now.

[randychase]

Okay, we have this much figured out.

The part is a BGA socket which as BGA pads on top, and pins on the bottom which we THINK are in the same location (one for one) as the BGA pads.

The BGA is rotated 45 degrees, so that the issue is a 45 degree array. I am not aware of the ability to array pads at 45 degrees in PowerPCB's decal editor.

My suggestion is that this part be created as if it was rotated 45 degrees. This means the BGA/pins are now orthoganal and in neat rows and columns. The outside of the socket and it's mounting pins and holes (6 of them) would be "rotated" 45 degrees relative to the BGA.

Then the entire part could be placed with a 45 degree rotation to make it resemble the data sheet, or not. There is no rule that says the BGA socket must be lined up vertical or horizontal either. But your board may dictate that it is.

To create a part like this, you can use trig to determine the location of the 6 mounting pins. But it's easier to use 2D CAD and quickly create the part in CAD and then rotate the entire thing. I used to use PADSLINK to create parts like this in AutoCad (it would take about 4 minutes) and then translate it to PADS. The good old days....

This should be interesting as an experiment using the new tools. I will give it a try.

[randychase]

Jenny,

Let me know if Plastronics agrees that the pins and pads are in the same location. This is vital need-to-know information.

[randychase]

Jenny, I have emailed you the part. You need to make sure the pin holes are one-for-one with the BGA holes, and you need to assign the BGA/Pin numbers in the decal editor, but the outline and mounting holes are done.

What I did was take an existing 17x17 1mm BGA from the pcbstandards library. DXFout to IntelliCAD. Using CAD, I rotated the part 45 degrees. Snapped lines to the corner pin and using the 2D command OFFSET, I created construction lines for the locations of the guide pins, mounting holes, and part outline. A simple Fillet command to add radius and trim the lines.

Now if I was really slick or had a good DXF translator, I could DXF the part back into PowerPCB. But since the BGA was existing and rotated 45 degrees, that would not work..or at least I could not see how to do it. So, I used Ordinate Dimensioning in CAD. My part and the BGA used the same Centroid. I rotated the part -45 degrees so the BGA was now in straight rows (normal) and the outline and mounting holes were now diagonal.


It only took a few minutes to snap dimensions to the holes and part outline corners.

In PowerPCB decal editor, I used the same BGA and added the pins for the guide pins and mounting holes using the XY coordinates. Then I added the new outline per the XY coordinates. SAVEAS a new part and I was done.

Is there a better way to have done an array of pins on a 45 degree angle? I don't know of any, but if anyone does know, that would be interesting.

[randychase]

Here is the part as done in 2D CAD after rotation and dimensioning:

http://www.pcbstandards.org/downloads/misc/bga-rotated.gif

[jreeves]

Randy,

Plastronics says the pads and pins are at the same location.

[randychase]

Cool. Then add drilled holes at all the BGA pins in the padstacks, assign the pin numbers, check the alphanumerics..and you should be good to go.

Let me know if you need more help.

[jreeves]

Thanks for all your help
Jenny