Looking at the replies to this message, and from my own experience, this
engineers request is
a reasonable one. If there is a component RES/cap that can be placed
100% on one side of the board,
then it is only sensible that the designer do so, even if it impacts his
"creativity". 

There is undoubtedly a saving involved in a set-up that is one component
- one side, reduced time/cost,
reduced possibility of error, increased ease of visual inspection (this
is a major benefit !)

However I am sure that the engineer would understand that with certain
components, i.e. clock or bus 
terminations, that placement is critical. Or that other components 10K
pull-ups or 270R pull 
down resistors there may simply be to many to place on the secondary
side due to spacing or other 
requirements. 

As with a lot of topics, this is case of horses for courses, and the
best answer may be "it depends".
For some components this is only sensible, if there are only two
resistors of a value it would be insane 
to put them on opposite sides of the board, but the chances of getting
all the 10K resistors on a 
dense design digital-board on one side are pretty slim.

Regards;

Derek

Derek J. Wynne
Design Engineer.
Toucan Technology Ltd.
I.D.A. Business Park
Dangan
Galway City
Ireland.
 
Telephone: +35391519913
Fax:          +35391519901
E-mail:       [log in to unmask] <mailto:[log in to unmask]> 
 




I have been asked by an engineer that I am working with to restrict the
top
side/bottom side placement of parts according to part values (all parts
are
0805's).  For example if I place a 10K resistor on the bottom side, all
10K's should also go to the bottom side.  He does not want me to mix
parts
of the same value between two sides.

He tells me this will significantly reduce assembly costs.  I have =
never
heard of such a thing.  Is he correct?  I believe the extra layout time
will negate any potential savings in assembly setup.  Any comments?


Mark Koitmaa
TechServ
http://www.techservinc.com

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