EEVblog #1325 - OPAMP Shootout - Datasheet Deep Dive

Part 2 in designing a better uCurrent.
A datasheet shootout between the Maxim MAX4239 and the TI OPA189
A deeper dive into the datasheet specs from the previous video, looking at gain bandwidth product, noise, supply current and voltages, offset voltages histograms, input bias currents, recovery and settling time, and slew rates.

#Opamp #Datasheet #Tutorial

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[Dave]

Dave, I don't know if you noticed but the TI part showing 3.0uV at 25C was listed as being at +-18V supply, while the Maxim part showed 2.0uV at 25C with a 5.5V supply. Isn't this actually a tighter tolerance for the given supply voltage from TI? Does the max offset scale up with increasing voltage? If it does, then linearly scaling the TI voltage vs max offset to 5.5V supply yields a 0.98uV maximum offset, more than twice as good as the Maxim part. I'm sure the value doesn't scale linearly, if it does scale with voltage, but I'm guessing you've got at least an equivalent spec between the two for the maximum offset voltage.

I'm also curious to find out if the 70pA vs 6pA input curent actually makes any difference when you sample and compare the two op amps.

Great video. It's nice that you documented what seems to be a great method for comparison of op amps. Thanks!

[andymouse]

Seriously can't wait, I love it when you cover this sort of "deepdive" stuff...cheers.

[Kocis]

Floating Dave is the best idea of 2020

[emorell]

Awesome videos! I am doing a PhD in experimental Physics and I do a lot of electronic designs for my group and I can tell you that I have learnt most of it from your videos over the years :)

[moienm]

Awesome Dave. This is incredibly useful for me. I am designing a current sensor actually and these are super relavent. I am measureing switch current, which is not as low as microamps but it is very high di/dt slew rate.

[Chris_Grossman]

The input current of cmos op-amps is primarily due to the input ESD protection diodes, not gate current. The 189 has a much higher supply voltage, thus higher leakage current,

I have a design video (optical oscilloscope probe) use the dual 2189

[flomojou]

Great! Really looking forward to the follow up...

[isaacbrorson]

To answer the question posed by a previous video, I’ve been seeing a lot more midroll ads, and you can tell which ones are placed by the YouTube algorithm because they perfectly interrupt the video at the worst time.

[edwardmonsariste]

Hey Dave!!!
I’m playing catch-up with your YouTube videos. Your videos are really great for us semi-pro’s that are trying to relearn electronics.
I had to google, “Bob’s Ur Uncle” along with other phrases. No worries now!
Thumbs up on the mailbag and multimeter tear down videos.

[leeunderwood]

I really liked the comparison via the datasheets - I'd love to see more of this.

[remontlive]

Thank you for that specific content!!! Unfortunately some people don't interesting, but I see it 2-5 times!!! I'm very appreciate such a adventure into a datasheets!

[barbasbandas]

I wish I was your student. The enthusiasm is what I like here. Thanks Dave

[eebaker]

I like the floating Dave concept. Very creative...

[DrFrank-xjbc]

Floating Dave is a nice new experience for viewers. Please don't use it too often, though.
The noise figures mostly correlate with the bias currents, i.e. low noise <=> high bias and vice versa. That was already the case with the old choppers from Intersil, ICL7650 and ICL7652.
Less noisy devices use FETs with bigger silicon area, usually.
See also explanation in AoE about the design of the hp34420A nV DMM, and its ultra large input FETs, which normally have several nA of bias current..

[jfcrow]

Looking forward to future video comparing bench performance of chips.

[tannerbass]

I just want a Dave Head flying around the screen 😂

[bengrant]

Definitely Dave head up the top where possible.

[Helectronics]

Thanks for the video, great explanation!

[Orbis]

Floating dave is the best dave :) I really like the idea of the flipped picture!
Btw I saw a Delorean on a sunday joyride yesterday.... beautiful car :D

[thomassynths]

It greatly saddened me when your head descended from the heavens to the pits of Tartarus. 16:16