OPA388: Ringing

Danilo A.

Part Number: OPA388

Hi Team,

Our customer is using OPA388 but a ringing appears everytime he change the state from low to middle or high to middle voltage from a DAC of a microcontroller. Please see the waveform below for reference. He mesured the output from the DAC but the signal is smooth. What could be the cause of the ringing signal?

Regards,

Danilo

over 4 years ago

0 kai klaas69 over 4 years ago

Guru 140200 points

Hi Danilo,

a schematic would be needed. I think there's a problem with the phase margin.

Kai

0 Michael Steffes over 4 years ago

Guru 48395 points

Well Dailo,

Looks like the square wave is 0 to 5V?? if so, are they really driving into the rails and then to a midpoint where the ringing is - pretty normal in that case as the op amp tries recover from internal node saturation.

0 Raymond Zhang1 over 4 years ago

TI__Guru* 77541 points

Hi Danilo,

Would you share the schematic with us including the DAC/MCU? The op amp may have shown instability issue with the driving load.

Best,

Raymond

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OPA388: Ringing