LM321: LM321LV current sense spec

Hey Brian,

The output swing from rail of the LM321LV is 1V from the positive rail.

Additionally, you would have to adjust the feedback resistors to have a gain of 10.

For rail-to-rail output, I would recommend the TLV9001.

Best,
Jerry

A 0.1 Ω shunt resistor generates 100 mV for 1 A. If you want to get the same voltage drop for a higher current, then you need a smaller resistor. (It might also be possible that your circuit requires a smaller maximum shunt voltage, or that it can tolerate a larger shunt voltage.)
In general, you choose R_shunt = V_shunt(max) / I_load(max).

The opamp does not care about the current; it simply measures the voltage drop over the resistor.

Both the LM321LV and the TLV9001 have rail-to-rail outputs, but the LM321LV datasheet does not explicitly mention it.

Hey Brian,

Clemens is correct about the selection of the shunt resistor. You can place whatever shunt resistor you would like for whatever current you would like on the input of the amplifier. All the amplifier is doing is taking the voltage generated across the shunt resistor and applying gain so that an ADC further down the signal chain can read this value and determine the current through the shunt. The maximum or minimum shunt resistor value is usually determined by how much it is acceptable for the voltage to shift at the shunt resistor, since this is ground for the system you are monitoring.

Once the size of the shunt resistor and maximum current is defined, then you determine what feedback resistors are needed to gain the input signal to the full scale range of the ADC.

Best,
Jerry