On Thu, Apr 16, 2009 at 8:53 AM, Olin Lathrop <olin_piclist@embedinc.com> w=
rote:
> davidcou@aol.com wrote:
>> The 1uF is a minimum recommendation but I always recommend a 0.1uF
>> additionally as close to the IC.
>
> Always!!? =A0That's just silly. =A0Do you specifiy the species of dead fi=
sh to
> wave over it too?

I knew someone who, as a regular part of their engineering, specified
"Sprinkle caps."

He'd add a few dozen capacitors across the power supply on one sheet
of the schematic, and told the layout guy to just sprinkle them all
over the board randomly (which is to say, the layout guy inevitibly
put them where it was convenient for him).  The boards were 4+ layer,
with power and ground layers, chips had their own (correctly rated)
bypass capacitors, etc.

Turns out he failed an EMI test once, and ever since simply placed a
bunch of caps all over to avoid later failures, "Cheaper than
retesting!"  ... except for the most popular products ...

Engineering by the seat of your pants.

Also, regarding the dead fish, I usually specify fresh salmon, and
have a grill standing by for the conclusion of the test.

-Adam

-- =

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