component layouts?

[Jim Patchell]

    Boy, talk about opening a can of worms.....

    Bypassing is both art and science.  My rule of thumb 1st of all, 1
bypass cap, to ground, for each power supply pin.  There are exceptions to
that rule of thumb, but that is another story.  It is also best to keep the
distance between the bypass cap and the power supply pins as short as
posible.  The idea of the bypass cap is to provide current for those peak
useage times.  For analog sutff, this is not quite as critical as for high
frequency switching, but the idea is still the same.

    Another general rule, I cannot think of a case where it is posible to
have too much bypassing.

    Now, cross talk is another problem.  Even with good bypassing, you are
going to want to look at the circuit and ask, where can extraneous signals
get into things.

    In conclusion, all I can say is that this is a pretty big subject.  I
don't know of any articles on the net that cover this.  You will probably
get enough replys to make an article though1 :-)

    -Jim


zapsn0n wrote:

> hi all,
>
> can anyone point me to some general online info & tips on component
> layouts, e.g. the placement of capacitors on DIY circuit boards to avoid
> crosstalk, etc etc  ?
>
> thanks,
> mark scetta