SAR ADC ENOB measurement in cadence

static or dynamic?

its Dynamic ENOB

Follow the IEEE Standard 1241 about ADC measurement methodology. Apply sinusoidal wave to the input and sampling it with numbers of samples≥2^N and make FFT of collected samples to get SINAD. Next calculate ENOB from formula ENOB=(SINAD-1.76)/6.02
Of course the sampling frequency cannot be an integral multiplicity of input signal frequency to avoid a leakage on FFT, etc.