5V Logic Bypass caps - SMD value/phy size recommendations?
James Paul email (remove spam text)
In my experience, I have found that a 20 uF or so electrolytic,
usually Tantalum, and a .1 or .01 uF to be sufficient. I haven't
tried to find an optimum value because these values always worked
for me in the past. As far as package size goes, the 20 uF is
usually in the 1210 package and the .1 or .01 is either the 0805 or
0603 package. Which package size I use depends on the size of the
IC I'm bypassing, the size of the board I have to work with, and the
number of components I have to mount. Regarding the hand built
status, most of the boards I work with are hand built (stuffed)
because the volume is so small. But I have no difficulty in
soldering packages as small as the 0603. With some difficulty, I
can solder smaller packages, but them my soldering tip size becomes
a major hurdle. I've also tried solder paste with some success.
Bottom line, the 1210, 0805 and 0603 packages work for me. They
probably will for you too. And that brings up my last point. If
these boards are to be manufactured after the prototypes have been
proven and/or perfected, check with the manufacturing facility and
ask them their preferences and/or limitations on component size.
It would be a shame to design a circuit, get it perfected with 0603
components, and then find out that the manufacturing facility can
only handle down to 0805 size components. Also, make sure you
leave enough space between components so that the Pick and Place
machines can get into posotion to place the component where it
belongs. I'm sure you know most of these points, but I figured I'd
mention them just in case you didn't.
On Fri, 02 June 2000, Jim P wrote:
See also: www.piclist.com/techref/index.htm?key=logic+bypass+caps
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