[SI-LIST] : BGA vs Leaded - summary

greg kimball (gkimball@indra.com)
Mon, 08 Mar 1999 08:59:01 -0800

All who have contributed.......thanks,

Just wanted to summarize what i have read:
1. That the BGA does have inherent lower parasitic L and C (no bond
wires and no packaging leads) and therefore better interconnect
transmission properties, - some details were given in the paper
suggested by Ravider at IBM "Noise computation in single chip...." IEEE.
(Thanks Ravinder)

2. Those advantages can easily be squandered by -
- long leads to the closest decoupling site
- long leads to the interconnect junctures

3. Moral of the story ??????
In order to take advantage of BGA, which does carry a manufacturing
cost premium, very careful interconnect strategies my be thought out
and put in place.
We have not talked about thermal aspects, but this is another tricky
area of consideration - underfills, number of balls to xfer heat out,
thermal gnd planes, etc, etc

Any parting comments ????

Regards,
Greg

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