Current voltage is 2.499930, which is 10uV below of what was yesterday (I kept DMM and the reference powered the whole time). I attribute this to testing the line regulation yesterday. I'm a bit disappointed.
Today I want to do two things:
1) clean the flux to see if there is any effect (I used quality flux, but there was also flux in the solder, so not sure how the two mix).
2) Heat it up with a hotairgun to, say, 61C for a few minutes, then let cool down and let's see how this affect the voltage.
3) re-arrange DMM crocodile clips to see if this makes a difference on the voltage. That's because ground lead carries some 0.4mA of quiscent current and I wonder if longer/shorter ground lead would affect the reading.
I wish I had a thermal chamber. I have a bottom heater, but it has up to 20C overshoot and poor regulation, so, not exactly suitable for our purposes
read the datasheet carefully: the maximum recommended operating voltage is 12.6 V.
So the behaviour above 12.6V is not specified.
Did you check for oscillations of the output in this state?
I would also recommend to use only one connection to the DMM
(and solder the other end to the reference instead of using crocodile clips).
13V is just 0.4V above recommended operating voltage, I decided to try it
. I have no intention to power the reference with voltages above 3.3V in a real circuit. I didn't check for oscillation with a 'scope, but looking at the readings, I think we'd see that on the plot if it was oscillating. There is only one DMM connected to the reference, and I know why you recommend this
.
As of soldering, I don't get it. Could you please elaborate more? The power and DMM are connected with crocodile clips. I don't have DMM leads that I could solder.