I am using ADA4940-1 for Single Ended to Differential for my Application.
I observed that ,when i gave 50mV to 1200mV as input and i got result with less variations (uV variations). If i am trying to give >1200mV , i obeserved big variation in the output signal (2mV to 8mV ).
Please suggest suitable configuration for ADA4940-1 for measurement of 50mV to 2500mV.
We can't be certain on what causes the variation you have observed unless you share to us your application. Schematic would be a great help for detailed analyses. What are your requirements? What would you like to do with the ADC driver? What signal are we dealing with? These information would be a good start.
Just to follow-up, what buffer are you using at the input of ADA4940?
Thank you for your Reply.
Please follow below Simplified Schematic for my present configuration.
1. Input Range is Uni-polar 0V to +3V Peak to Peak
2. Unity Gain
3. Uni-polar Supply Voltage ( 0V to +5V )
4. Vocm = 2.5V
1. If there is any signal violation in above configuration?
2. I observed more than 8mV variation in the above configuration at input voltage >=2.5V marked as Red in above Table.
3. What is the maximum Peak-Peak input voltage support for ADA4940-1 SOIC package (in Unity Gain Configuration) ?
Please suggest the recommended Schematic for measuring of 0 to +3V input range.
Presently, We are using AD8605 as a Voltage Buffer in ADA4940-1 input .
Hi Dhanalakshmi S,
Upon reviewing your schematic, I see no violations in your configuration. However, I noticed on your results that some things are off the expected value. Did you use tight tolerances for your gain setting resistors? Let's take for example when your input is 1.260 V, VoP and VoN should be 3.13 V and 1.87 V respectively. But in your results, it's 3.094 V and 1.835 V. Could you also check the value of your Vocm, output of AD8031? The expected offset should not be above 1mV. See below figure for additional reference.