Re: gEDA-user: SMT/Through Hole Mix

[sdb@xxxxxxxxxx (Stuart Brorson)]

I don't see why you wouldn't do as much SMT as possible.  There is no
advantage to though-hole stuff that I am aware of.  (I welcome
corrections on this point.)  You can do hand assembly and rework of
both through-hole and SMT down to (arguably) 0603 
components (or maybe even 0402 if you have good eyesight and non-shaky
hands).  As for power stuff, lots is availale in SMT versions, so
that's not a consideration.  Through-hole stuff is going obsolete
anyway.  Finally, SMT stuff lends itself to automated assembly, which
-- in the long run -- will be cheaper. 

Ultimately, you should talk to the folks who will stuff your board.
They can offer better advice tailored to your situation than we can
here.

Stuart


> 
> I have a design that's very low production quantity(~50 pieces per year) 
> that has a couple of chips that only come in surface mount versions.   Does 
> anyone have any opinions on what the lowest cost assembly option is with the 
> design, is it better to attempt to do the whole board in SMT with just a few 
> components through hole(things like power components) or do you do the board 
> mostly through hole except the 2 surface mount chips(noting that one is 48 
> pin tqfp).  Or do you go with two boards, one with all surface mount(except 
> for perhaps the connector between the boards) and then do a second board 
> with all the through hole components.
> 
> We've managed to keep things strictly through hole until this point in time. 
> Unfortunately it's no longer viable to go all through hole with new designs 
> of any complexity.
> 
> I appreciate any opinions.
> 
> Thanks
> 
> 
>