I need to measure current though a sensor and feed it to the ADC of a micro-controller. The ADC input voltage range does not match the sensor's output voltage range. I searched and found that op-amps solve this problem. However, I need to know the output impedance of the sensor or input impedance of op-amp (both same.) Does the burden resistance used at the output of sensor represent the output impedance of the sensor? If not then how can I calculate it?
I have attached the image for reference. I'll be using some other op-amp instead of OPA320 mentioned in this image. My purpose for asking the question is to get some help in selection of suitable op-amp and input/output resistor, capacitor etc. I am using a closed loop Hall effect current sensor to measure around 50A square wave AC current and feed it to the ADC. There is no limit to burden resistance as per datasheet of the current sensor. This is the datasheet for the sensor.
Vin at the input of the op-amp will be the output of the current sensor and practically will introduce some resistance that will affect the operation of ADC drive circuit. I need to know this output resistance of the current sensor. The sampling frequency for the ADC will be 25 kSPS and I cannot allow more than 400 ns as total ADC conversion time for one sample.