For the same reason a policeman wouldn't trade in his Kevlar reinforced vest
for a nylon one,,just because city council passed an ordinance prohibiting
criminals from carrying anything but pellet guns.
Dewey

> -----Original Message-----
> From: Graham Collins [SMTP:[log in to unmask]]
> Sent: Thursday, November 08, 2001 11:38 AM
> To:   [log in to unmask]
> Subject:      [TN] High Tg FR-4
>
> Hello Technet
> A question for bare board gurus.   Is there a difference in reliability
> between high Tg and regular Tg FR-4 ( IPC-4101/24 vs IPC-4101/21) in a
> vehicle type application?
> The end use application is less than Tg of /21 material, so not in the
> glass transition range for either material.
>
> Typically - is the CTE different between these two?  (I expect that
> depends on the manufacturer to some degree).  If there isn't a high
> temperature operating requirement, why select the high temp FR-4?
>
> Thanks!
>
>
>
> regards
>
> Graham Collins
> Process Engineer,
> Northrop Grumman
> Atlantic Facility of Litton Systems Canada
> (902) 873-2000 ext 6215
>
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