ts-7000
[Top] [All Lists]

[ts-7000] Re: noise level on MAX197 on 7250

To:
Subject: [ts-7000] Re: noise level on MAX197 on 7250
From: "j.chitte" <>
Date: Tue, 18 Mar 2008 18:36:05 -0000
--- In  "Michael" <> wrote:
>
> > > Looking at the TS-7250 schematic, it seems there isn't any 
external
> > > capacitance. The datasheet (as I'm sure you've seen) suggests 
4.7uF
> > > at REF (pin26) and .01uF at REFADJ. Schematic shows .1 and 4.7uF
> > > on REFADJ.
> >
> > Yes , I'd looked into that. I actually think this is a TS
> > documentation error since there is a capacitor on pin 26 , but 
since
> > it is a microscopic smc device I can't tell its value. It seems 
too
> > small to be a 4.7uF though!
> 
> I've forwarded this report to our hardware engineer and indeed 
there was a 
> documentation error.  To summarize their response, "the MAX197 ADC 
does have 
> a 4.7 uF cap on its pin 26."  The TS7250 schematic available on the 
web site 
> has been updated with this correction.
> 
> 
>  ______   Best Regards,
> |__  __/                  Michael Schmidt
>    ||                   Software Engineer
>    ||echnologic Systems (EmbeddedARM.com)
>    || (480)    16610 East Laser Drive #10
>    |/ 837-5200   Fountain Hills, AZ 85268
>        http://oz.embeddedarm.com/~michael
>

Thanks Micheal, 

that should help in the future.

Could you address my main issue here? Is it realistic to try to get 
12 bit accuracy off these boards (within the limits stated in the 
MAX197 datasheet) or are we expecting too much?

I'm quite willing to believe this noise may be coming from the 
external cct but don't want to spends days/weeks fault finding only 
to discover that I am trying to achieve the impossible.

To be clear , I'm not refering to absolute accuracy here. Just 
whether it is possible to get a clean reading +/- 1 LSB while 
sampling just one channel.

I need to make a decision very soon now on whether these boards are 
able to fullfil our spec requirements.

Thanks for any information your engineers can provide.

best regard, 

jacques.



------------------------------------

Yahoo! Groups Links

<*> To visit your group on the web, go to:
    http://groups.yahoo.com/group/ts-7000/

<*> Your email settings:
    Individual Email | Traditional

<*> To change settings online go to:
    http://groups.yahoo.com/group/ts-7000/join
    (Yahoo! ID required)

<*> To change settings via email:
     
    

<*> To unsubscribe from this group, send an email to:
    

<*> Your use of Yahoo! Groups is subject to:
    http://docs.yahoo.com/info/terms/

<Prev in Thread] Current Thread [Next in Thread>
Admin

Disclaimer: Neither Andrew Taylor nor the University of NSW School of Computer and Engineering take any responsibility for the contents of this archive. It is purely a compilation of material sent by many people to the birding-aus mailing list. It has not been checked for accuracy nor its content verified in any way. If you wish to get material removed from the archive or have other queries about the archive e-mail Andrew Taylor at this address: andrewt@cse.unsw.EDU.AU