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OPA189: OPA189 input current noise spectral density.

Lukas Kuenzi
Intellectual 400 points
Part Number: OPA189

Hi,

In the OPA189 datasheet there is no plot for the input current noise spectral density.
I would like to know how the input current noise spectral density is vs. frequency and if there is some noise peaking around the chopping frequency?
Is it correct that the chopping frequency is around 125kHz?

Thank you and best regards,
Lukas

  • 0
    TI__Guru* 93105 points

    Hi Lukas,

    Characterizing input current noise spectral density of a CMOS op amp such as the OPA189 is highly difficult because of the extremely low current levels. The OPA189 typical is 165 fA/√Hz at 1 kHz. Therefore, characterization of the parameter is only performed at a fixed frequency such as 1 kHz, and not across frequency. A typical graph of input noise spectral density vs frequency is not developed, or provided.

    The OPA189 chopping frequency is approximately 150 kHz.

    Regards, Thomas

    Precision Amplifiers Applications Engineering