Variation in voltages measured during cold start of DAC. Expected?

[LTig]

Yeah, I suspect that when measure at different time, the number might be different by 0.001V, due to error range of multi meter. But, I expect the number to stay stable when doing measurements.

The error of a multimeter usually is much higher than +/- the lowest digit. So changes between measurements could stem from the multimeter and not from the DUT.

However, as you wrote ...

It was interesting to note that a E30 could not stay stable for a while when cold boot. X16 was very stable (powered on for a full day before measurements).

... that the X16 is more stable than the E30 hints that it's not the multimeter which is wrong.