Hi folks,
for my new weekends project i want to design a small, portable, low-ish cost calibrator. At this moment i am trying to find out which voltage reference to use for the precision ADC/DAC (and multimeters vref of course)
one of the Vrefs i am considering is the ADR3425ARJZ-R7, not the best but the low frequency noise should be low enough to be less than a 16 bit LSB
Datasheet:
http://www.mouser.com/ds/2/609/ADR3412_ADR3420_ADR3425_ADR3430_ADR3433_ADR3440_AD-878965.pdfAs you can see, the feedback path is not explicitely connected to the output pin and i wanted to use this at my advantage. The Load regulation is not that good BUT if i buffered the voltage reference output and took the feedback after the buffer opamp i should achieve a Vref independent on the current load and at the same time eliminate the offset introduces by the opamp so i could focus on a low noise, not necessarily low offset one.
The initial accuracy and the line regulation isn't that good either but, again i could use the two at my advantage: i could power the reference from a DAC and vary its supply voltage, hence adjusting the output to the required precision.
is all of that something that makes sense? (Let's forget about the temperature for one second, assume it to be fairly constant)