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I would like to use INA 217 for my application. My application involves amplifying a single ended signal in mV range. I will set the IA to have a gain of 1500 and the maximum bandwidth is 50kHz. The output of the IA is connected to a single stage passive low pass filter (cut-off frequency 100kHz) before the single-ended output is connected to the ADC.
Since the application is to amplify a single ended signal, I use the configuration as shown in the Figure above. Instead of connecting the inverting input directly to ground, I noticed with other IA I have if I connect a resistor to the inverting input and then ground the inverting input, the IA output will have a much lower DC offset, the DC offset was reduced from 100mV to 50mV. The resistor has the same value as that in RC high pass filter connected to the non-inverting input.
Can anyone confirm that it is the right way to use INA 217 for single ended signal?
The 1k resistor on the inverting input will help reduce the offset voltage due to input bias current. The INA217 is a very low noise amplifier. It very low noise is important in your circuit, you might benefit by reducing this resistance to a lower value (such as 100 ohms) and injecting a trimming voltage to adjust the offset.
This circuit will require a dual +/- power supply.
