With this universal circuit you can measure all important op amp DC specifications.
DUT op amp with almost any unity gain frequency and with high open loop output resistance can be measured correctly!
S-Audio.Systems // Op amp DC parameters measurement
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As measurement example : DC parameters of NE5534 from various manufacturers
DUT op amp with almost any unity gain frequency and with high open loop output resistance can be measured correctly!
S-Audio.Systems // Op amp DC parameters measurement
------------
As measurement example : DC parameters of NE5534 from various manufacturers
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It looks really useful. What DAC 0 and DAC 1 are is unclear. I would like to see the whole setup and what it would take to duplicate it, e.g. source and acquisition setup.
Well, some/many DC specifications - you can't measure recommended operating voltage as its inferred from statistical measurements on many units!
Actually I don't see how this circuit can measure offset current v. differential input voltage either, or even whether the opamp has back-to-back diodes on its inputs.
It won't be sensitive enough to measure bias or offset currents for a JFET or CMOS input opamp, which are in the picoamp range.
You need to be able to drive the inputs to the rails to test for no-phase-inversion, not clear the input has the range required for this (how many DACs support +/-15V ?). I suppose you could measure at +/-5V and hope its the same at other supply voltages.
But still its pretty capable!!
No problem, you can measure at least 30 units and do some statistical calculations.
Typically recommended operating voltage is defined on the design stage, and can be lowered after corners characterization.
open S1 and S2, change differential input voltage by changing outputCM voltage
change value of R3, R4 and make low leakage through the pcb.
current value of R3, R4 is for bipolar input op amps, and allows you to measure >30-100pA
you can do measurements on any voltages. If needed, only gain stage is everything you want.
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There's an large ratio resistor divider formed, so no, doesn't allow large differential inputs to be chosen without closing S2 and possibly frying R2.
My point is "all DC specifications" is a lot to claim - "most DC specifications" would be fairer. Many opamp datasheets have graph after graph of interesting DC stuff, some of which cannot be gleaned using this test jig. In fact many graphs are against temperature which isn't addressed at all.
yes, for correct results you must be in linear region, so no large diff voltage. And you can not fry R2 🙂
which for example?
Ok i understand you, if you like you can call "all important DC specifications".
Nothing interferes you to measure DUT at different temperatures.
I see that you poorly understand op amp characterization process, that's why so many misunderstandings.
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