Electrical – Op-amp with constant gain for small signal(mV)

current measurementgainmeasurementoperational-amplifiershunt


simulate this circuit – Schematic created using CircuitLab

I want to measure current using shunt resistor and I want to amplify the voltage over the shunt using an op-amp. The shunt resistor gives 60mV @ 60A. I tried LTC 1050(http://cds.linear.com/docs/en/datasheet/1050fb.pdf) but for input <20mV the gain is not constant. The op-amp has a supply of +/5V.
Vout is the signal that I want to send to ADC NI 9215, which has ±10 V measurement range and 16-bit resolution.
Do you know what features the op-amp should have for this purpose?
Which op-amp do you suggest to use?
Which circuit is the best for this application?


Best Answer

Do you know what features should have the op amp for this purpose?

for that particular circuit, you need dual supply (or a beyond-the-rail opamp), zero offset opamp. it is not a good circuit to measure current.

google current sense amplifier.