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.
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.
DC performance- low Vos, Vos drift with temperature/time, and high open-loop gain particularly.
Best regards, Spehro Pefhany
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.
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.
Often any or all of the above. Low DC offset is one parameter I typically associate with them. Low Input bias current too.
Graham
Hello Mook,
Usually DC performance (low offset).
Regards, Joerg
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. :>
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.
They are able to achieve a precise output, and thus have a high gain, high PSRR, high CMRR plus the rest that was mentioned.
Rene
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