Bit of an older topic, but I was just looking for some kind of affordable voltage reference myself.
There doesn't seem to be a whole lot of information shared about these things unfortunately.
I would still like to add some important points to the discussion, especially on the first couple of comments.
It all depends if you're looking for the
best possible vs
worst case scenario.
Unless I can really specify something, I would go for the last one.
Looking at the long term stability, this will eventually lead to say something like 15-20ppm or so.
Which is an equivalent of 0.002%.
Some devices seem to have an asymptote here, while others just seem to drift forever?
So instead of trying to bring that number down, one can also just use that number as a starting point.
Everything less will be just better in performance.
Obviously it depends on your application, but 0.022% total error is pretty good or very good in most cases.
Although there are two questions from my side;
1 - It seems a little unclear what they sometimes mean by the max accuracy?
According to this article;
https://e2e.ti.com/blogs_/archives/b/precisionhub/posts/ic-long-term-stability-the-only-constant-is-changeThey see it the rated accuracy as the max accuracy after x many years (see end of the article). While others sometimes seem to use this term as the initial value?
So in the case of the MAX6226, this 0.02% is worst case after many years.
2 - I assume that the long-term stability rating counts for when the device is powered on? Or is there also some natural drifting, even when the device is not being used at all? Certain epoxies and other bonds age over time as well for example.