I am trying to build a current sensing circuit (two channels), with no requirement of precision (i.e., is current passing over some threshold whatnot). The (somewhat generic) circuit I am implementing is this:
The circuit works as expected with LM358 of TI. But I insisted to use a Rail-to-Rail opamp and got this LMV358 from Diodes Incorporated.
I used 470k %1 as R2's and 3k3 %1 as R1's in the circuit. The output is around x0.9 of the input. The gain is not around 140 as expected. My shunt resistor is 20mOhms, and current is around 50 mA. So my input voltage difference happens to be around 1 mV. My supply is around 5.1 volts.
However, it does not work.
I take the LMV358 out of the PCB, resoldered the LM358, and everything works fine again. Actually, when I attached the LMV358 first, only one channel (one of the dual opamps) was working. Once I detach it and attach to an independent breakout-board, it works fine.
Isn't this kinda weird?