I'm new to these forums, so I hope I could explain my problem well.
We have a design in which we are trying to measure current from a motor phase, in order to be able to limit the PWM signal. This signal has 0-28V range and its frequency it's 12kHz (the duty could be from 5% to 95%). In order to reject the common mode, we chose the AD8216 amplifier because its specifications were adjusted to our design, and its gain and ofsset could work with the isolated amplifier from the next stage. The LTSpice simulation worked, following the schematic below, but measuring in the real circuit, we see an unexpected voltage input of 2V approximately. This voltage is the differential voltage at input, and it is greater than the opamp maximum ratings. In our calculations, Rshunt value was chosen in order to have 230mV with 14A approximately, so this measure has no sense to us. Should we implement a filter input stage or have we another problem? The layout to the resistor is not perfect, so we will try to wire it directly in order to cast aside the possible parasitic resistance from layout.
The AD8216 is connected in-phase, so as it's indicated in Figure 31 from the datasheet, and we aim to measure the bidirectional current.
Thank you very much in advance.