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nice opamp

Discussion in 'Electronic Design' started by John Larkin, Dec 8, 2007.

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  1. John Larkin

    John Larkin Guest

  2. Joerg

    Joerg Guest

    Neat! Thanks for the hint. Best of all it's around $0.50 in quantities.
    Come to think of it, the good old days are right now. If only the young
    lads and lasses would get off that couch, toss the Playstation into the
    corner and build something.
  3. Jim Thompson

    Jim Thompson Guest

    But they don't know how... nor do they care :-(

    ...Jim Thompson
  4. OBones

    OBones Guest

    Heck, I'd like to know how, but most the time I asked teachers, they
    answered: why do you care, buy a ready made module and hack around it.
    Basically, use blocks and connect them together...
  5. Ecnerwal

    Ecnerwal Guest

    ....and why does it come in two versions with reversed power pins, but
    otherwise exactly the same (unless I missed something), I wonder? So you
    can get the wrong one and blow them up?
  6. John Larkin

    John Larkin Guest

    Darn, it was too good to be true.

    I like the saturation detector; I've gotta try one and see if it's any
    good. Lots of opamps wind up badly if they rail.

  7. BobW

    BobW Guest

    You got really bad teachers. Why, back in the good old days...

  8. Nico Coesel

    Nico Coesel Guest

    Hmm that goes for my oldest son, but my youngest son (okay, he is
    nearly 6) seems to be developing a real interest in technical stuff.
  9. Guest

    That does make it ceaper than the LM10, which has been around for a
    while now.
  10. Joerg

    Joerg Guest

    One prof told us that when we are grown up transistors will bne obsolete
    and it's all chips. ROFL! Luckily I totally did not believe him and that
    fact provides me income now.
  11. Winfield

    Winfield Guest

    That goes to the history of sot-23 opamps. Be careful.

  12. Best regards,
    Spehro Pefhany
  13. John Larkin

    John Larkin Guest

    Right. CMOS amps tended to have v+ and v- reversed. Another thing I
    like is that the 33503 version has the "standard" pinout.

  14. "Jan Panteltje" ...
    Also be prepared to use it only with GND properly connected to proper soil
    or rock: the input resistance is expressed in terra-ohms ;)

    Apart from typo's like that it looks like a nice chip. Would have preferred
    Vin+ at another corner to keep the input current really at << 1pA, it's not
    easy to guardring on a small chip like that.

  15. NSC started the "wrong" pinout, IIRC, but the rest of
    the world didn't follow. No doubt Motorola wasn't sure
    and wanted to cover both bases when they introduced this
    IC. It's interesting how old it is; my datasheet copy
    in my computer is dated 4.5 years ago, and it's rev 7
    (it's now at rev 10). The oldest copy at PartMiner is
    rev 3, dated Feb 2000, so this chip must be more than
    eight years old.

    This opamp isn't that appealing, it's 30nV input noise
    is a little on the high side, for example, and so is its
    1.2mA supply current. That would be too high to use in
    the 250V current-sense ground-output thread.
  16. Joerg

    Joerg Guest

    Yes, but you can build a pre-amp that is able to run on a single AA
    cell. Ok, most of us can also do that with transistors but young lads
    often can't. They need a shrink-wrapped solution in a plastic package
    along with a detailed app note on how to wire it up.
  17. John Larkin

    John Larkin Guest

    I'm doing a tachometer thing, and using this as the integrator for
    variable-reluctance speed sensors. Given a sensor on the housing of a
    big rotating machine, sorta near some gear teeth on a shaft, a little
    noise doesn't matter. This amp is ideal here, and cheap!

    If the saturation detector works, I can get rid of some integrator
    clamp stuff, always a nuisance.

    These vr pickups output voltage proportional to frequency, and one can
    give you millivolts to >100 volts p-p as the speed varies.

  18. Ben Jackson

    Ben Jackson Guest

    The MMA2260 datasheet only has labels for 7 of the 8 pins on one side
    (but spread out so they span all 8), which moves the power pins, and
    then to keep you on your toes the text version calls 'Vdd' 'The power
    supply ground' and 'Vss' 'The power supply input'.
  19. Fred Bartoli

    Fred Bartoli Guest

    OBones a écrit :
    1) your teacher is a moron

    2) he almost surely don't know how to design things either

    3) get your butt off and learn and build things by yourself. There's no
    better way.

    It's just a matter of motivation and work.
    When I was 16 and we just learned about derivatives, knew almost nothing
    about integrals, logs and exponentials, ode,... I went to an electronics
    componants show in Paris and bought a few electronics books.
    The selection process was pretty simple: just quickly skim through some
    and picked up those that made me think: "Great, I understand almost
    nothing so I'm sure I'll learn something". I just keeped re-reading them
    until it made sense. 1 year and a few more books later I was OK with
    complex fequencies, laplace & fourier transforms,...

    Just don't be shy :)
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