Hello,
I'm unsuccessfully using an LMP8645 to current sense on the high side of a DC circuit. I'm supplying an amplifier with 12V DC whose current draw range is 60±10mA. I'm interested in monitoring that current draw. I'm using a 10 ohm shunt resistor in front of the amp, and a gain resistor of 21K. In+ is seeing 12V and In- is seeing ~12.4V nominal. My calculations of 21k/5k = 4.2V/V suggest that I should see 2.5V at the amplifier's output. I'm powering the amp with a single 5V source. However, I'm measuring 4.9V at the amp output. I chose this amplifier because it was advertised as accepting high common mode voltages w.r.t. the source. Did I misinterpret the spec? Does anyone see what I'm doing wrong?
Dario