US Sources for old ICs
tshoppa at wmata.com
Thu Oct 27 08:10:42 CDT 2005
William Donzelli wrote:
> Ever notice that in the 60s and 70s, they did not use flatpacks all that
> properly? For some reason, the philosophy was to have the leads quite
> long. No real reason for that, is there?
The "official" way of mounting flatpacks also required you to
mill a chunk of the board away so the IC sits in the PCB, and
then you have to weld (not solder) the leads to the PCB. Maybe
in the 60's it made sense but with multilayer boards today getting
rid of all those signal traces (as well as the ground and power
planes!) just won't fly.
It's possible that the long leads had somethng to do with welding
I got the impression that flatpacks weren't about increasing
density but were an over-reaction to problems with hermetic
seals and bent leads.
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