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Precision Op-amps ?

Discussion in 'Electronic Design' started by mook Johnson, Jan 6, 2006.

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  1. mook Johnson

    mook Johnson Guest

    Many opamps are described as "precision". What criteria are they talking
    about when the say precision

    Is it DC performance? noise? drift? linearity?

    Just curious.
  2. Pooh Bear

    Pooh Bear Guest

    Often any or all of the above. Low DC offset is one parameter I typically
    associate with them. Low Input bias current too.

  3. Joerg

    Joerg Guest

    Hello Mook,

    Usually DC performance (low offset).

    Regards, Joerg
  4. Guest

    It's the usual marketing crap. I understand it to mean low DC off-set
    (trimmed to something appreciably less than 1mV), but it is noticeabel
    that the auto-zeroing op amps that offer offses around the 1uV level
    aren't labelled "hyper-precision" as they would be if the guys who
    wrote the ads had any clear idea of what they were talking about.
  5. Pooh Bear (Graham) wrote...
    Low distortion under dynamic conditions is another important aspect.
    In this case high bandwidth (GBW) and high slew rate are important.
    A related issue involves high-speed precision (24-bit) A-D converters
    with differential inputs, which may specify an RC filter on the input.
    This means the driving opamps need to have low distortion when driving
    a low-Z load at high frequencies. Thus the opamp's output impedance
    at high frequencies is an important issue. Beauty is, as beauty does.
  6. DC performance- low Vos, Vos drift with temperature/time, and high
    open-loop gain particularly.

    Best regards,
    Spehro Pefhany
  7. I think, most often, offset voltage, then offset current, then bias
    current and maybe low frequency gain and maybe noise. Drift is taken
    care of with a tight offset voltage and current spec.
  8. Ken Smith

    Ken Smith Guest

    No-one makes "just another op-amp". There are low current, high speed,
    low noise and etc op-amps. If they can't call them any of those, they
    call them precision. :>
  9. They are able to achieve a precise output, and thus
    have a high gain, high PSRR, high CMRR plus the rest
    that was mentioned.

  10. Winfield Hill wrote...
    A part number meeting these criteria is LTC's LT1468. I used these
    in my 24-bit 200kSps s/p-dif board design, RIS-574, which I posted
    to a.s.b.e. a few weeks ago, seeking comments. I'll post it again.
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