Hello,
Does anyone have any suggestions for this thread:
http://e2e.ti.com/support/amplifiers/etc_amplifiers__other_linear/f/18/t/86349.aspx
I didn't know how to move it over to the Precision Amplifiers folder.
Basically, I have a high side current shunt on a 12V battery that should give me between +/- 5mV of voltage drop when the load current flows. I hooked everything up as shown in Figure 1 of the data sheet. I use 100k resistors for both Ros and RL, which should give me a gain of 100. I have 3.3 V supply for V+, and am providing a 1.5V Vref using the wiper of a 10k variable resistor.
The first problem is that the Vref voltage doesn't seem to have any effect on the output voltage. In fact, the voltage at the Vref pin measures 12V (even though I have connected a 1.5 V reference as explained earlier, the chip is feeding power through the pot). Secondly, when the shunt voltage changes even slightly, the output voltage immediately up past the 3.3V rail to around 6 V. How is this happening? I have tried three different chips and they all do the same thing. Note that I have used a MSOP8 to DIP adapter and currently have everything breadboarded.
Thanks in advance.
Mark