AnsweredAssumed Answered

AD5781 VREFNF can not be setted to 0V.

Question asked by BOEING on Apr 13, 2017
Latest reply on Apr 17, 2017 by msamera

Dear Engineer:


   I connect the AD8062AR to the AD5781ARUZ by following the instruction of AD5781ARUZ. What I want to achieve is to make the VREFNF to 0V. The diagram about negative connection is shown in below:




The connection about positive connection is shown in below:





In realistic the OPAMP I used is not AD8062 but LF412. During the test, the voltage of eight U3 pins I measured is shown as the list below:

Pins Voltage


1 0.48

2 0.00

3 0.00

4 -15.02

5 5.01

6 5.00

7 5.00

8 15.11

We can see that the voltage of VREFNF is not 0V, but 0.48V. What caused?