[sdiy] AD1866 ADC on Single Supply

[William Berzinskas]

seems like i've pretty much got it that way.. AGND and DGND meet up at the
DAC..  Although, I think i'm getting some noise thru it when the uC sends
new data..  Any idea whats going on there?

thanks
--billie

----- Original Message ----- 
From: "Harry Bissell Jr" <harrybissell at prodigy.net>
To: "William Berzinskas" <WBERZINSKAS at nc.rr.com>;
<synth-diy at dropmix.xs4all.nl>
Sent: Wednesday, December 01, 2004 12:28 PM
Subject: Re: [sdiy] AD1866 ADC on Single Supply


> Hello William
>
> BIG question, short answer
>
> Agnd and Dgnd are both tied to ground... but the
> question
> is where. Usually, large currents with fast rise times
> flow in the digital part of the circuit, these can
> interfere with the analog signals if they share the
> same ground return, You try to design so that the
> analog ground and the digital ground touch at only ONE
> place to avoid the interaction.
>
> Often the data sheets will suggest how to do this, a
> quick method is to make the ONLY connection between
> these grounds right at the A/D chip itself.
>
> of course that is not always possible (what if there
> were two A/D for instance... :^)
>
>
> --- William Berzinskas <WBERZINSKAS at nc.rr.com> wrote:
>
> > Looking over the datasheet, I'm seeing Agnd and
> > Dgnd..  But, I'm using a single supply..   How do i
> > deal with this?
>