Hi team,
My customer is using LM331 to convert a input voltage to square wave output. The schematic is as below:
AIin is the input to LM331 and Fout is the output of LM331. We found that when AIin is connected to GND, Fout waveform has some random pulse output. Please see the waveform as below:
Purple:LM331 input AIin
Yellow:LM331 Fout pin
Blue:Optocoupler output AIin*
Green: NA
Zoom in single pulse on Fout waveform as below:
As you could see, the LM331 in stable @0V. But LM331 will output some random pulse. So could you please help look into this issue? Thanks.
Best regards,
Wayne