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OPA211, funny/peculiar graph in datasheet

Discussion in 'Electronic Design' started by Martin Griffith, Oct 19, 2007.

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  1. Fig 4 on page six, the unity gain thd looks a bit strange, for a +-
    15v rail

    Anyone tried one of these little beasts?

  2. Phil Allison

    Phil Allison Guest

    "Martin Griffith"

    ** 100% STALE NEWS !!!!!!!!!!!!

    Phil Hobbs has done this piece of dumb trivia to death already.

    ........ Phil
  3. Not in this NG

    Your search - opa211 - did not match any documents

  4. Phil Allison

    Phil Allison Guest

    "Martin Griffith"
    "Phil Allison"

    ** Yes, right here on October 11 - you dim witted, PITA fool.

    ** No - your dumb search was 100% defective:

    From: Phil Hobbs <>
    Subject: "Maybe the universe has always been like this, but I've been too
    wrapped up in myself to notice..."
    Date: Thu, 11 Oct 2007 22:08:53 -0400
    Organization: Posted via Supernews,
    Message-ID: <>
    User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:
    Gecko/20070802 SeaMonkey/1.1.4
    MIME-Version: 1.0
    References: <>
    In-Reply-To: <>
    Content-Type: text/plain; charset=ISO-8859-1; format=flowed
    Content-Transfer-Encoding: 7bit
    Lines: 7

    To all you op amp gurus: I posted a question and picture in
    alt.binaries.schematics.electronic about weird THD behaviour in an
    otherwise very nice op amp, the OPA211.


    Phil Hobbs

    ** So - **** off

    - you copycat TROLL.

    ...... Phil
  5. I should have known that I should have searched for
    "Maybe the universe has always been like this..."
    rather than OPA211.

    You too can be a bit of an idiot at times, just occasionally, not
    really that often, really.......honest

    BTWNot a single reply..... and it should be Mr. Phil Hobbs,

  6. Phil Allison

    Phil Allison Guest

    "Martin Griffith"

    ( snip copy of Phil Hobbs Oct 11 post on SED )

    ** A search using "opa211" and specifying SED gets one hit - Phil Hobbs
    post on Oct 11.

    YOU stuffed up - fool.

    ** Piss off - wanker.

    ....... Phil
  7. Yeah, I'd like to see what was said in that abse discussion. But
    whatever it was, it seems clear that dasheet plot can't be relied
    upon. And I have no idea, Martin, how your mild question set off
    the bomb. OK, I went and looked; here's the done-to-death thread
    (I know you've already read this, but others might like to see it,
    and the abse threads aren't archived):

    * Phil Hobbs:


    As I was helping someone with a TIA design this afternoon, I had
    occasion to read the data sheet for the OPA211, which appears pretty
    similar to the LT1028, except that it's a bit more stable and doesn't
    come in a plastic DIP. It has a curve of THD+noise vs rms output
    voltage that I found very odd (see attachment).

    Everything goes swimmingly until the signal swing on the inputs
    about 1V rms, and then it hits the wall. This is at a kilohertz, mind,
    so it isn't an ordinary slew rate issue. It's also _way_ within the
    CM range, because the plot specifies +- 15V supplies.

    Since the problem surfaces at the same input voltage swing makes it
    look like something in the input stage, but what in the world could
    be as slow as that?

    So what's up with this amp?

    * John Larkin:

    That graph makes no sense whatever.

    If the numbers were different, I'd say that some input back-to-back
    diodes were conducting... but not at 1 KHz. Also, fig 3 sort of
    contradicts fig 4. 140 dB is an interesting number, too.

    Is it an artifact of the test circuit, fig 41?

    If you figure it out, let us know.

    * Phil Allison:

    ** Nothing - Fig 4 is just plain wrong.

    Read the text where it states THD < 0.0001% when G = 1 and
    output level = 3 volts rms.

    * Fred Bartoli:

    It seems they nicely screwed the DS there.

    Not only the G=+1 curve is, ahem, a bit off, but it seems the G=+11
    curve could the G=+1 one: the G=11 curve shows [email protected], which is
    the stated figure for the G=1 case.

    They have a documentation feedback link in the page footer and I
    just sent feedback. Let see what they say...
  8. Your search - opa211 hobbs - did not match any documents.

    So you are blaming me that google is not exactly perfect?

    Have a good night, bye, (and you use too much white space)

  9. Phil Allison

    Phil Allison Guest

    "Martin Griffith"
    " Phil Allison "

    ** Works perfectly when I try it.

    YOU are one dumb shithead.

    ** Works perfectly when I try it.

    YOU are one dumb shithead.

    ** **** off - you BLOODY IDIOT .

    ........ Phil
  10. On Fri, 19 Oct 2007 15:20:52 -0700, in Winfield

    So - **** off
    The f/b link is not for tech stuff, only wrong sort of font stuff

    Thank you Win for the copy, none of that showed up on my NG reader or
    in abse. I'll dig out LT1028 in the morrow

    But should I apologise to Phil? This could be a first in SED?

  11. Phil Allison

    Phil Allison Guest

    "Martin Griffith"

    ** That is *very* hard to swallow.

    Such an obscure issue, never mentioned on SED or ABSE prior to Phil Hobbs'
    posts, somehow gets " independently discovered " by another poster only 7
    days later.

    Amazing ....

    ........ Phil
    did not return much, please take your meds. It's probably Google
    redirecting .com to .es domains, and don't take sed so seriously.

    You still use too much white space.

  13. Phil Allison

    Phil Allison Guest

    "Martin Griffith"
    "Phil Allison"

    ** This cretinous CUNTHEAD thinks it ever so clever to take words out of
    context for effect.

    Sure sign of a yet another moronic autistic.

    ** But a search on " opa211 hobbs " gets just one hit.

    As does any similar search using GG's Advanced Search option - which is
    how any sane person tries to find a post in their archive.

    ** You still breath far too much air for something so utterly worthless.

    Drop dead & save the planet from your CO2.

    ........ Phil
  14. Phil Hobbs

    Phil Hobbs Guest

    Wow, my very own flame war.... Reminds me of my lottery
    mum bought me a lottery ticket once that hit for $100--which makes me
    the only person I know who's won something in a lottery without ever
    having bought a ticket in his life. On the other hand, the $100 was
    nicer. ;)

    I suspect that Fred got it right--that the G=1 and G=11 curves are
    backwards, the labelling is messed up (distortion vs Vin not Vout), and
    the nonlinearity in each case is from the output banging into the rail.
    It seems to happen near 10V rms, which is +-14V peak, not bad going
    for +-15V supplies. I'm still not designing anything based on those
    curves, though.


    Phil Hobbs
  15. Phil Hobbs

    Phil Hobbs Guest

    Actually, that's sort of interesting...the other Phil Hobbs who comes up
    is an Australian troll who talks mostly about rugby...must be my
    Antipodean self. I wonder if there's a Northern Hemisphere Phil Allison? ;)


    Phil Hobbs
  16. Sign up to my server, 500$US or 10€ a year, it's just not there,90 day
    retention, AFAIR, just one message, the original, by Mr. P.H, and I
    could not find it through, so can we please call this
    sillyness to an end.

    And the idea that *only* 2 english speaking people notice a problem in
    the same datasheet, independantly, and queried it, within a week is
    not unknown. I should have thought it would be more.

    I'm more annoyed about the guys who produced the datasheet in the
    first place for not spotting it, and geting us into this stupid rut

  17. Phil Allison

    Phil Allison Guest

    "Martin Griffith"

    ** But a GG's search on " opa211 hobbs " gets just one hit.

    As does any similar search using GG's Advanced Groups Search option -
    which is
    how any sane person tries to find a post in their archive.

    YOU ARE A TOTAL ASS !!!!!!!

    ** The one prolonging the agony is YOU


    ** So yo have ZERO comprehension of probability.

    As well as every other damn thing.

    ** With what ??

    That pointy lump of wood on top of your fat neck ???

    ........ Phil
  18. Yes, Mr. John Woogate

  19. My guess is that the typo is the +-15 volt supply
    specification. If the amp is powered by +-2.5 volts, the
    narrow common mode range would explain the curves.
  20. Probably, but you are such an easy wind-up.....-)

    /me is trying to imagine the reply, even before hitting send

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