I want measure voltage drop across resister of value 0.1 ohm to 2 ohm.
so suggest the op amp for the same.
please find attach circuit file.
supply voltage 400V.

 

This ap note shows working with high CM input range circuits, page 47.

http://www.ti.com/lit/ml/slyy154/slyy154.pdf


http://www.ti.com/lit/an/sboa295/sboa295.pdf A 400 V solution


An approach that possibly could be modified for higher V operation -

https://www.edn.com/design/test-and...side-current-monitor-operates-at-high-voltage


Regards, Dana.