Hi,
I have a question regarding the accuracy of the DAC81408RHA's internal voltage reference.
According to the datasheet the initial accuracy should be +/- 2.5mV with an ambient temperature of 25°C. However, I have measured the VREFOUT on a few devices and got results ranging from +2.496765V (-3.235mV) to +2.494524V (-5.476mV) at room temperatue. Measurements were done with a calibrated benchtop multimeter, Agilent 34470A).
Even when I take into account the output drift (over time) and typical thermal hysteresis, I don't expect to get these big deviations.
The VAA /VDD supply voltage is +4.9865V and stable, no noticeable ripple. The REF and REFCMP pins are decoupled as per datasheet, 150nF and 330pF, respectively.
Have these big voltage reference deviations been seen before? What could cause this big deviations?
Thanks,
Jeroen