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ADS131M06: ADC Noise measurement to achieve resolution

Deepak c
Prodigy 100 points
Part Number: ADS131M06

Hi,

Can you please help me in understanding noise level lost in conversions?

I wanted to measure 300VAC with the resolution of 1V

how i will make sure that with this ADC, I will achieve this resolution.

Regards,

Deepak

  • 0
    TI__Guru 57326 points

    Hello Deepak,

    Thank you for your post and welcome to our forum.

    1V / 300 Vac is approximately 50 dB of dynamic range: 20 x log10 (1 / 300). With the ADS131M06, you can achieve up to 102 dB at Gain = 1, or up to 80 dB at Gain = 64. Your input signal will have to be divided down to within the full-scale and absolute voltage ranges of the ADS131M06.

    Regards,

    Ryan

  • 0 in reply to Ryan Andrews
    Prodigy 100 points

    Hi Ryan,

    Thanks for answer.

    How we can validate?

    How data can be processed?

    I have seen some of the noise floor level measurement?

  • 0 in reply to Ryan Andrews
    Prodigy 100 points

    Well,

    Just to correct below

    20xlog(1/300)= (-)50 dB not 50dB

  • 0 in reply to Deepak c
    TI__Guru 57326 points

    Of course, technically then it is 20*log(300/1). We generally speak of dynamic range in absolute terms to describe the difference between two magnitudes: the largest and smallest signals measured by the system.

    You can validate the noise performance of the device by shorting the input pins together and biasing them to a mid-supply common-mode. The results of the peak-to-peak and RMS noise that you measure will be very close to the data presented in the Noise Measurements table in the data sheet.

    Regards,

  • 0 in reply to Ryan Andrews
    Prodigy 100 points

    Hi Ryan,

    Got it..

    I have designed circuit already with with 91k (Upper) and 1k (bottom)

    Now i wanted to measure noise floor with the data that i have processed via UART.

    How i will come to conclusion that we are achieving resolution of 1V

  • 0 in reply to Deepak c
    TI__Guru 57326 points

    Hi Deepak,

    A change of 1 V in your input signal will produce a change of 10.9 mV at the ADC input using the resistor divider circuit you described. This is much better than the resolution of the ADS131M06.

    Regards,

    Ryan