Re: Simple multi-channel serial ADC (8-ch)?

Hi Jörg,
7022 is with $4 delivering 10 AD ports with 12 bit.
More like $5/1k, at least in the US:
http://www.digikey.com/scripts/DkSearch/dksus.dll?Criteria?Ref=130267&Site=US&Cat=33358756

$ 3.98 from
http://www.analog.com/en/subCat/0,2879,762%255F%255F0%255F%255F0%255F,00.html

But not that much stock which always has me a bit worried. You couldn't
even buy 1000 of them for that price right now because they only have 597.
Some of the non-stocked versions show this little note: "Obsolete item;
call Digi-Key for more information."

May be but this is only a example. Guess your very special AD wouldn't be in
stock too.

the ADuC7022 may not be the cheapest solution, Atmel may have cheaper
ones, or Reneas, or...

May be you want to use a very cheap ATtiny with a 4067 as Mux? I'm sure this
isn't to beat. for low data rate you can create your own quad slope AD using
the cheapest controller to be found.

The Analog MicroConverters do really have excelent AD-units. That's what
I know, this is what you didn't guess, me too, but we tested it.
AD is known for analog excellence. Did you do a hard test down to the
noise level against a stand-alone ADC? And look at clock beats and stuff?

I saw the sample results from 1 Hz full scale sine wave without a plane or
such special features just given to the minikit sampled there and
transmitted this online with 2 kSps over UART (UART-USB-Bridge - Yes powered
from USB! but with onboard 3V3 regulator). It looks fine without missing
codes, only a few toggles around the last bit. In my view a very good
result. I didn't expect more than 9 bits.

The other issue is that it's difficult to find local coders that know this
uC.

It is a ARM7 controller and the only thing you need is the data*** (handy
vs 100 pages) and little knowledge of Ansi C. There are good examples from
analog and around in the net.
But If I were you I would use a cheap one and make my own dual or quad slope
with a few 4051 mux in front of it as I remember you want to measure DC
signals and mostly you design as cheap as possible for mass production

Marte


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