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LME49721: Corner Freq at 2KHz?

Needhu Gunasegaran
Intellectual 2880 points
Part Number: LME49721
Other Parts Discussed in Thread: LME49720

Hi Team,

My customer has the following question. Could you please help us here?

The datasheet says the 1/f corner frequency is at 2000Hz. For an audio opamp this would be quite bad and I do not believe that this is correct.

 

So far our measurements did not show a noise increase at this frequency (see attached image). The measurement shows some noise spikes at 150Hz due to 50Hz voltage supply, but an increase of noise already at 2kHz is not visible

 Can you tell me if the given 1/f corner of 2kHz is right?

  • Do you maybe have measured noise plots over frequency regarding voltage and current noise densities?
  • Does only the voltage increase at this point, or the current noise too?

Thank in advance,
Needhu

  • 0
    TI__Guru** 102995 points
    Hi Needhu,

    The 2kHz spec for corner frequency must be a typo. It should be 200Hz instead.
    You can base in other similar process devices specs, like LME49720; figures 34 and 35 from LME49720 data sheet show the plots for Voltage and Current Noise Density vs Frequency.

    Best regards,
    -Ivan Salazar
    Applications Engineer - Low Power Audio & Actuators