[sdiy] digital control of CV

[Tim Parkhurst]

On 9/3/07, ASSI <Stromeko at compuserve.de> wrote:
> On Sonntag 02 September 2007, jure zitnik wrote:
> > now from what i've seen such things are mostly done by multiplexing
> > control knobs, getting the multiplexed control signals (CVs?) in an
> > ADC, enter digital domain (patch store/recall), and then back to
> > analogue through a single fast DAC that constantly cycles over all
> > the CVs. separate modules' inputs each have a sample+hold circuit
> > that samples when that module's CV comes up.
>
> AD makes a series of "Infinite S&H" and multichannel DAC chips (16, 32
> and 40 channels with a variety of output ranges 10, 12 and 14bit
> precision, with and without offset and gain error correction - AD55xx)
> that can be controlled via SPI.  About the only downside is the need to
> deal with fine-pitch BGA packages that makes a four-layer board
> mandatory.
>
>
> Achim.

I can see soldering SOP and TSSOP packages with some practice and
patience, but there is no way you're going to solder a BGA without
some very expensive equipment (screen printed solder paste, reflow
oven, maybe even an x-ray machine for inspection of the results). And
repairing / replacing a BGA? That's a subject that even makes
professionals nervous.


Tim (also makes professionals nervous) Servo
-- 
"Imagination is more important than knowledge." - Albert Einstein