Hello, I want to know how ad8422 chip uses single power supply to amplify bipolar signals? My simulation gain in Multisum is less than 1, which can not reach 100 times when the chip is powered by dual power supply.
Hello, I want to know how ad8422 chip uses single power supply to amplify bipolar signals? My simulation gain in Multisum is less than 1, which can not reach 100 times when the chip is powered by dual power supply.
OK, thank you for your answer.In order to amplify the bipolar signal, I added VCC / 2 bias voltage at the negative input. The simulation result is not ideal and the amplitude is too small. This bias method can be correctly implemented on another op amp AD8616.So I don't know how AD8422 can achieve the same amplification effect as dual power supply under the condition of single power supply.Thank you for helping me fix it.
OK, thank you for your answer.In order to amplify the bipolar signal, I added VCC / 2 bias voltage at the negative input. The simulation result is not ideal and the amplitude is too small. This bias method can be correctly implemented on another op amp AD8616.So I don't know how AD8422 can achieve the same amplification effect as dual power supply under the condition of single power supply.Thank you for helping me fix it.
The input signal need a bias voltage but not AD8422's IN- in single power system. And the ref pin of AD8422 need to connect to the bias voltage with low source impedance. So the correct circuit as below:
