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TLV320ADC6140: question regarding data sheet

Part Number: TLV320ADC6140
  • Number: CS1083208
    Contact: moshe FRID
    First name: moshe
    Last name: FRID
    Short description: Typical Characteristics curve
    Phone: 972974174117411
    Email: moshef@adcom.co.il
    Company: adcom
    Company phone:
    Language: English
    State: Open
    Provide case details or comments:

    TLV320ADC6140

    at the data sheet page 17 there is a curve of : Figure 18. FFT With Idle Input With DRE Disabled

    we use that chip X 2 with 4 analog mems diff microphones each:

    my customer want to check the design quality by restoring that curve

    he ran a that checking and got more noise than at that curve in low freq.   :

     

    my question is how to make all the conditions that are with that curve

     

     1. linear phase decimation filter -how to config it

    2.  all performance measurements are done with a 20-kHz, low-pass filter, -how to add it?

    3. A-weighted filter - how to do it?

    4. what is ''IDLE INPUT'' - we did not connect the Mic. to the board but the serial capacitors 1uF stay so do i need to connect a 2.5K resistor instead in order to fix impedance matching issue?

     

  • MF

     

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  • Hi Moshe,

    Table 21 shows the configuration options for the digital filter. The linear phase decimation filter is the default. The 20kHz low-pass filter and the A-weighting filter are not on the device. Those are a part of the measurement tool, such as an Audio Precision. 

    You could try the 2.5k resistor, but I would just ground the inputs with the serial cap. Another option would be to connect to some signal generator (like an Audio Precision) but don't drive any input.

    Best regards,

    Jeff