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INA181-Q1: output distortion

Part Number: INA181-Q1

Hi Expert,

My customer is using INA181-Q1 in their OBC product. And met some issues, need your support on that. 

Below are the circuit of INA181-Q1 in the simulation tools, the waveform also attached as below. I(R7) is the current waveform of shunt resistor, V(n032) is the output pin of INA181-Q1, V(n033) is the waveform on C20, V(n034) is the waveform on R11. You can find the output is distorted compare to the input waveform. 

The frequency of I(R7) is about 300KHZ which is close to the bandwidth of INA181A1-Q1. I am not sure if it is related to the bandwidth. So may you kindly check the reason of distortion and give some suggestions to avoid the distortion? 


Ethan Wen

  • Hi Ethan,

    Yes, the output is distorted due to bandwidth limiting. The large transient in the input signal will also be limited by the output slew rate. I would suggest switching to the INA296, which has a greater max BW of 1.1MHz and slew rate of 8V/us, the automotive Q1 version will also be released soon. You can try simulating with the INA296A2 model and you will see that the output will not be as distorted.