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I am using ADA4898 op-amp. Without connecting any elements to the circuit at the output of the IC, I see a negative voltage. Is my IC broken?

schematic

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schematic

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1 Answer 1

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You're running the op-amps open loop so the slightest difference between the inputs will drive the output to saturation.1

Connect the output to the inverting input to make a unity gain buffer and the output should go to 0 V.2


1 Op-amps have very high gain of 100,000 to 1 million or more. That means that any input offsets due to imperfections of the op-amp get amplified by that factor and show up on the output. For that reason we use negative feedback to control the gain and correct any non-linearities in the amplifier.

2 With negative feedback the amplifier output will settle down when the inverting input is at the same voltage as the non-inverting input.

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