I am using ADuM361 chip for one of my sensor data acquisition project. I came across a strange issue with the internal 1.2V bandgap reference . I have followed the decoupling recommendations mentioned in the datasheet and 1.2V is generating properly on my board. The problem is i am using the same 1.2V for adding an offset to my sensor circuitry. It is basically an opamp stage and 1.2V is added as offset just to get the readings within the ADC measurement range. An image is attached for reference. So when i am using the sensor circuitry i can see the 1.2V bandgap from the AduCM361 is overshooting ( reaching upto 2 V ). Do you have any details on the current sinking/sourcing capability of the internal bandgap reference ?? Any recommendations while connecting the 1.2V bandgap reference to other circuitry ??
This is a possible solution but we don't recommend connecting the bandgap 1.2V anywhere because it might cause inaccuracy for measurements using ADC. This use case was not characterized in the part…
It is not recommended to use the 1.2V internal reference for this application. This pin must be connected to ground via a 470 nF decoupling capacitor
Can i use an external buffer and use the bandgap 1.2V reference for this application
This is a possible solution but we don't recommend connecting the bandgap 1.2V anywhere because it might cause inaccuracy for measurements using ADC. This use case was not characterized in the part.