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ADS114S08EVM: About calculation method of ENOB in the IC

TJJ
Prodigy 30 points
Part Number: ADS114S08EVM
Other Parts Discussed in Thread: ADS114S08

Hello

At first, sorry for my cheap English... I would like to know about calculation method of ENOB.

How was the ENOB indicated result of Delta-Sigma ADC EvaluaTIon Software?

The parameters needed to calculate ENOB cannot be found on any datasheet. (parameters that like "SNR"..."SINAD"...)


Please teach me how to refer to the parameters related to ENOB

Best regard TJJ

  • 0
    TI__Guru** 113765 points

    Hi TJJ,

    The ENOB calculation in the ADS114S08EVM GUI is really effective resolution.  For AC type ADC measurements where an AC signal is applied, then you would use the equation ENOB = (SINAD - 1.76dB)/6.02.  However for DC type measurements then what is a better indicator for the resolution is the noise in the measurement and the effect of noise on the result.  This is discussed in section 8.1 of the ADS114S08 datasheet.  The calculation for effective resolution uses equation 1 and relates to the RMS noise in the measurement.  Equation 2 shows the calculation for noise-free resolution and relates to the peak-to-peak noise.  

    The noise measurements shown in the noise tables is based on measurement of 512 consecutive samples with shorted inputs for the given conditions.  The shorted input case will give the best possible condition resulting in the lowest possible noise of the ADC.

    Best regards,

    Bob B