Regarding Package creation

[Raju_epigon]

Dear friends,


While creating Packages with respect to datasheet, how much minimum tolerence we need to keep. Eg, Original PAD in datasheet is 0.5mmX1mm means what is the PAD tolerence and give me tolerence for PTH components also. What is the minimum clearence between PAD and Drill.


Can i get any books for this, or kindly any by advise to me.


Thanks & Best Regards,
R. Balasubrmaniaraju

 

[Old Nick]

I'm not exactly sure what you mean by clearance between pad and drill. If you're talking about DIL pads, (the ones wih holes through the board and a solder pad), then your packeage creation tool will have these already.
But for minimum clearance distances it'll be your PCB manufacturer which will supply these guidelines.
If you're making SMT packages, just make the pads slightly bigger than the footprint (look at other SMT pads for comparison)

This link may also help.
**broken link removed**
Hope this helps.

Nick