How about a digital pot.? You'll need only 3 pin to control it (SPI). You
spent a little more on the pot butreduce cost using an smaller chip and an
smaller PCB.

Marcelo Y.


> >I can do it with
> >28-pin PIC and resistor networks, but the product won't
> >stand the cost and size gets messy with the larger chip and
> >all those resistors.
>
> Hmm, I would have thought that an F87x and a F84 would have been very
similar in
> cost, but then I have not gone looking for production quantities.
>
> How about an F87x with SIP resistors. If you can get SIP networks with the
R
> value in a 10 pin pack, would give 5 individual resistors, and another
similar
> with 2R, giving a total of 4 SIP packs. Have only done a quick mental
think
> about what is required for R/2R networks, you may still need a couple of
single
> resistors, but then you will be making zillions of them, so surface mount
won't
> be a problem?? Certainly you can get 4 isolated resistors of the same
value in a
> 1206 size package priced at GBP0.055 ea. for 50 off (minimum order) from
RS
> Components, with a fair range of values available.
>
> If you get real lucky you may be able to get an R/2R network in a single
> package, although I could not find one on a quick sweep through the RS
> Components CD.
>
> But seriously I doubt you will get much cheaper for combined board
space/cost
> combination.
>
> --
> http://www.piclist.com hint: The PICList is archived three different
> ways.  See http://www.piclist.com/#archives for details.
>
>

--
http://www.piclist.com hint: The PICList is archived three different
ways.  See http://www.piclist.com/#archives for details.