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LM158: LM158, voltage following

Part Number: LM158

Hello everyone, the problem is this. A signal with a positive or negative amplitude of 12V and a frequency of 10KHz passes through the voltage follower and the signal waveform changes. The front and rear edges of the square wave signal become slower. The positive voltage  drops to very small. The voltage follower is composed of LM158 chip. (Various methods have been tried ,like the grounding resistance has been tried 10K or the resistor is not connected). However, the output waveform is still changed from a square wave to a triangular wave.

 What caused this result?

The bandwidth of the LM158 is large enough: Unity-Gain Bandwidth of 1.2 MHz

(the op amp is connected to the positive and negative power supply)
Thank you !



                                      Voltage follower circuit diagram

                                                Voltage follower output signal waveform

  • Hello,

    If I understand your application correctly, you are violating the abs max of the part.   Input voltage should not be lower than Vcc- (pin 4) by more than 0.3V.

    Also the input common mode voltage needs to be higher than Vcc- minus 0.3V and lower than Vcc+ minus 1.4V.

    Note that we have a spice model for the LM158: