I have an application where I'm using a 0.001 ohm sense resistor and the TS2010H Current Sense Amplifier with a 5V supply and VREF1/VREF2 tied so that the reference is 2.5V. The output goes through an RC circuit into an A/D converter input to a micro.
The circuit is monitoring an AC current waveform through the sense resistor. Nothing fancy. With any amount of amperage flowing through the sense resistor, I have verified that the sense resistor is generating the correct voltage (Vsense = Isense x 0.001), The issue is the TSC2010 output is 22 times greater, not 20 times greater. This is of course 10% error instead of the specified 0.3%, and it is causing big problems to the device. I've checked every one of the error contributors detailed in Section 5.6 of the specification (pages 30-32), but none of them are the cause. It just seems the gain is off by way more than it should be. What could I possibly be doing wrong?
Thank you for any ideas.
UPDATE: The cause was circuit noise. After 2 days of fighting this, I finally rerouted the traces from the sense resistor to the op-amp with a twisted pair. That solved the problem. It was noise all along. Sorry for the false alarm.
