Searching \ for ' [EE] AD7829 problems' in subject line. ()
Make payments with PayPal - it's fast, free and secure! Help us get a faster server
FAQ page: www.piclist.com/techref/index.htm?key=ad7829+problems
Search entire site for: 'AD7829 problems'.

No exact or substring matches. trying for part
PICList Thread
'[PICLIST] [EE] AD7829 problems'
2001\11\15@181438 by brandon

flavicon
face
This AD7829 has a reference output of about 4v instead of 2.5 +/- 2% like specs say. I plug it in without any connections whatsoever (except -Chip Select) and it has this output.

If anyone has experience in these I'de like to know why its doing this. Could it be burnt out? It seems to do conversions ok, except for the horribly off reference.

Thanks.

-brandon irwin

_____________________________________________________________
Get your free email here at http://www.e-ha.com

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


2001\11\15@182325 by mike

flavicon
face
On Thu, 15 Nov 2001 15:12:36 -0800, you wrote:

>This AD7829 has a reference output of about 4v instead of 2.5 +/- 2% like specs say. I plug it in without any connections whatsoever (except -Chip Select) and it has this output.
>
>If anyone has experience in these I'de like to know why its doing this. Could it be burnt out? It seems to do conversions ok, except for the horribly off reference.
>
>Thanks.
>
>-brandon irwin
>
>_____________________________________________________________
>Get your free email here at http://www.e-ha.com
Could it be that there is an option bit somewhere to turn off the
reference to save power ?
--
http://www.piclist.com hint: The PICList is archived three different
ways.  See http://www.piclist.com/#archives for details.


2001\11\15@201535 by Tim Hamel

picon face
In a message dated 11/15/01 3:15:19 PM Pacific Standard Time,
spam_OUTbrandonTakeThisOuTspamE-HA.COM writes:


{Quote hidden}

Well, according to the datasheet, either you can supply Vref or use the
internal Vref. They also mention decoupling the Vref pin to AGND via a .1uF
cap. They also the same for the Vmid pin. See if that helps.

-Tim

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


2001\11\15@205224 by David Huisman

flavicon
face
Brandon,

I missed the earlier posts but looking at this... What do you mean the ADC
has a reference output of about 4V ?
If you are measuring at Vref, this pin is an input and would need to be tied
to either your reference voltage or VCC.

In the data sheet they recommend you connect an external reference of 2.5V
+/- 2%. (AD780)

Also, I note the IC is available in 3V and 5V versions, is your supply
correct for the version ?

Best Regards

David Huisman



{Original Message removed}

2001\11\16@154026 by brandon

flavicon
face
Thanks for the help, your suggestions have worked.
Still seems kind of strange that I'm getting 4v from an input...hehehe

brandon irwin

--- David Huisman <.....david.huismanKILLspamspam@spam@ADVMININGTECH.COM.AU> wrote:
{Quote hidden}

>{Original Message removed}

More... (looser matching)
- Last day of these posts
- In 2001 , 2002 only
- Today
- New search...