I am using ADUM3190 as isolation amplifier and observing gain variation from 1.9 to 2.8 with input voltage of 0.3V to 1.5V. I have a resistive divider network at the input (total resistance is 3Mohm) and power with 5V for VDD1 and VDD2, both are isolated with each other. The voltage measurement is from 200V to 1000V. But as per the datasheet, the gain is between 2.5 to 2.7 for WT/WS devices. The schematic is same as the test circuit provided in the datasheet fig.29 with ROD = 4.7kohm.
In one of the post, it is mention about the limited input impedance of the ADUM3190, but datasheet mentioned as 10nA input bias current, which is good enough for my voltage measurement between 200-1000V
Please help me to understand this behavior and make the device work as per the spec.
Let me know if any more information required.
According to the datasheet specs, when you use the EAOUT2 output, there are errors in the EAOUT output plus the errors in the EAOUT2 output that you need to include in your total error. Each of these outputs have Gain, offset and linearity errors, and the offset errors can be the largest error.
Thanks for the response. The gain and output offset has error of +/-0.1V which is very wide for my application, Also I observe the variation of gain is different for difference board. How do I arrive at the correction for these output. Could you please suggest.
Today I tested the device in stand alone (without input resistor divider and feed input from power source and output load), I see the gain is as per the specification (~2.6). I don't see much of error in my readings as mentioned for output offset and gain variation.
To better see what is happening in your application, would you be able to share your circuit for the ADuM3190 and the measured input and output voltages? Also, would you please share the circuit and measured input and output voltages when you "feed input from power source and output load"?