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Date:	Sun, 21 Jul 2013 11:00:35 -0400
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Subject:	Re: [geda-user] H-bridge footprint help
From:	Bob Paddock <bob DOT paddock AT gmail DOT com>
To:	geda-user AT delorie DOT com
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On Sun, Jul 21, 2013 at 10:27 AM, Stuart Brorson <sdb AT cloud9 DOT net> wrote:

> 1.  Since the output is on both pin 4 and pin 8 (the tab), you can
> stand the part upright, with the tab in the air,

> 2.  You can lay the part down on the board,

> Which one you want to do will be largely determined by how much power
> the part will dissipate.

The other major determining factor for stand/lay, be sides space and
power dissipation, is the system environment.

If the unit is subject to high vibration levels (this is a motor boat control?)
 or high G levels (dropping the motor when mounting), standing parts
tend to break (or be ripped in the case of G forces) their leads at
the solder junction after a while.
Alas no way to know how long "a while" might be.

I've seen this failure most with standing electrolytic caps.  Some
have had the leads break *inside* the case so the part looked fine.
:-(

I've learned the hard way it is best to lay parts down when you can.
Don't overlook the stress of bending the leads to get that done, as
that can also lead to system  failures.

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