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Am I right in thinking the 741 was.....

Discussion in 'Electronic Design' started by Genome, Oct 17, 2006.

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  1. Genome

    Genome Guest

    1) Some sort of weirdo **** up invented to demonstrate the designers ability
    to be clever.

    2) Some sort of weirdo **** up invented by the designer after management
    stuck the oar in because the original design was just too simple and they
    wanted everyone else to have a hard time ripping it off.

    3) It makes obvious sense given the constraints of processing at the time it
    was designed.

    4) It's just obvious!

    5) The designer was the only person who could come up with this shit at the
    time but drank beer down the pub with his mate(s) and they hatched a plan
    for the gradual release of shit to different companies.... at a price.

    DNA
     
  2. Jim Thompson

    Jim Thompson Guest

    You alright there, DNA?

    (1) The 741 wasn't too shabby an OpAmp (for its time).

    (2) The published schematic is NOT the real schematic... ask (IIRC)
    Raytheon... they copied the schematic with disastrous results ;-)

    ...Jim Thompson
     
  3. Genome

    Genome Guest

    That narrows things down.....

    So, is

    http://www.national.com/ds/LM/LM741.pdf

    slightly right in the right sort of way?

    Did Bill and Ben have their heads together when Mike gave Raytheon the
    original design but they upset Mike and Mike met Bill who spoke to Bob and
    then Ethel came up with the master plan whereby Bob, Bill, Martin, Mike and
    other Bill edited the masks to come up with something entirely different....
    but made up another diagram and then spoke to Dave and other Mike about an
    offer for second sourcing on a particular understanding that certain things
    would not happen as long as certain other things did....?

    Sure fine, I just felt stupid enough to try and figure out why and then
    thought I'd check for hidden (conspiracy theories) reasons unrelated to my
    limited comprehension of 'this bit goes up, so this bit goes down'.

    DNA
     
  4. How DARE you insult Mr.Rube Goldberg with such a demeaning language!

    --
    Paul Hovnanian mailto:p
    ------------------------------------------------------------------
    A limerick packs laughs anatomical
    Into space that is quite economical.
    But the good ones I've seen
    So seldom are clean,
    And the clean ones so seldom are comical.
     
  5. Guest

    Just so so
     
  6. Jim Thompson

    Jim Thompson Guest

    IIRC that looks correct. I used a lot of those in thick-film hybrid
    LDO regulators for the Hughes TOW Missile in 1970-73. I needed that
    exact configuration to make it work. Other _so-called_ 741's wouldn't
    work.
    That's a common-mode feedback loop in the middle (if that Q8-Q9-Q3-Q4
    circuitry is throwing off your comprehension). Q10-Q11 is your
    classic Widlar logarithmic current mirror.

    Do I need to write another OpAmp tutorial?

    ...Jim Thompson
     
  7. Genome

    Genome Guest

    Wouldn't dream of it and I'm sure he would deny it anyway.

    DNA
     
  8. Genome

    Genome Guest

    No!!! And I don't need none of your silly hints either.

    For the moment it might be enough to say it is meant to be..... I'll be off
    to bed now but I shall move things up and down tomorrow.

    DNA
     
  9. Jim Thompson

    Jim Thompson Guest

    <SMIRK>

    ...Jim Thompson
     

  10. Or his design review by Mr Murphy.


    --
    Service to my country? Been there, Done that, and I've got my DD214 to
    prove it.
    Member of DAV #85.

    Michael A. Terrell
    Central Florida
     
  11. John Larkin

    John Larkin Guest

    I remember, in days of yore, making the decision to use 741's in a big
    shipboard control system program. They were more expensive than
    uA709's and such, burger+fries+milkshake maybe, but had three big
    advantages: no front-end zenering/latchup modes, no external
    compensation, and a decent current limit. That sort of stuff was
    impressive in those days. They were fine for most analog/controls
    stuff, had few quirks and pretty good DC specs. The PNP front-end had
    chronic popcorn noise, so they sucked for really low-level stuff.

    What's a good gp opamp now? I like the LM7301, SOT-23, r-r i/o, OK DC
    specs, 4 MHz, 5v to +-15v supplies.

    John
     
  12. Joerg

    Joerg Guest

    Hello John,
    I liked the uA709 better. Compared to the 741 it felt like a hotrod but
    that also meant you could wreck out easier. Of course, the hottest of
    all amps from those days is the uA733 which was also remarkably cheap
    almost right from the start. I made a lot of RF gear with those. There
    were times when a 733 sold for about the same price as a 741 in the
    local stores (in Germany) but you got a Kawasaki instead of a moped.

    Nice, but expensive.
     

  13. Wasn't the µA733 an early video amplifier?


    --
    Service to my country? Been there, Done that, and I've got my DD214 to
    prove it.
    Member of DAV #85.

    Michael A. Terrell
    Central Florida
     
  14. Ban

    Ban Guest

    balanced out, but only +/-6V supply
     
  15. SioL

    SioL Guest

    What's a modern-day replacement for NE5532?

    SioL
     
  16. Genome

    Genome Guest

    So, it was item 3.

    I'll make no claims but, after a bit of head beating, I see something. Shit,
    now you've told me, I can't even claim to have almost got nowhere....
    Bastard. Now all the Girlies down the pub want to meet the real Jim
    Thompson.

    DNA
     
  17. Jim Thompson

    Jim Thompson Guest

    Sure they do. One of the worst put-downs I ever endured was from a
    _very_well_put_together_ female employee who told me I was "a father
    image" to her :-(

    ...Jim Thompson
     
  18. Stings, don't it? I can still remember the first time a gal on the
    street called me "sir". 8-(


    Best regards,
    Spehro Pefhany
     
  19. Jim Thompson

    Jim Thompson Guest

    Youngster. I've been called "sir" for at least 25 years ;-)

    And "N" has finally succumbed to using the "senior" discounts.

    I've been using them for years. To me a discount is a discount... I
    don't care what you call it.

    The airline senior discount can be quite substantial... I don't tell
    them I'm a working senior... the laptop is "just for watching movies"
    ;-)

    ...Jim Thompson
     
  20. John Larkin

    John Larkin Guest

    Gosh Jim, are there chip-designer groupies?

    John
     
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