All ADCs for high bit counting (bigger than 14 bits) use Sigma-Delta
conversion for a lower cost production. Sigma Delta use a capacitor ramp
measurement based on voltage comparison. They use integration, discharge
and other techniques to get great precision and accuracy. Actually they
are quire precise, and much cheaper than the regular instantaneous
multiple voltage comparison technique used in lower bit count.

Personal experiences about ADC's point the latest Linear Technologies
LT2400 and LT2408 one of the easier to use, with a low cost. They run at
24 bits !!! in just 8 pin DIP package for the 2400.  The 2408 has an
embebed input mux at the chip.

Wagner.

Mark Skeels wrote:
>
> Hi, folks.
>
> TelCom has a new AtoD part, a TC3401. It claims to be a 16 bit AtoD
> converter and it's cost at 1000 pcs is $4.63 US.
>
> I never heard of a Sigma-Delta AtoD converter before. Can anyone tell me how
> it works, and has anyone had experience with this new part?
>
> Thanks on advance,
>
> Mark