In the preliminary datasheet for the ADuCM360, it says the ADC's Integral Nonlinearity (INL) at Gain=1 is +/-15 ppm of FSR (same as in the ADuC7060). If I do the math for the number of accurate bits in this worst-case nonlinearity scenario, it comes to log2(1/15E-6) = 16 bits. This means at some voltage, the ADC is not better than a 16 bit converter?
For example, the LTC2449 has 18.6 bits and the ADS1258 has 18.25 using this same calculation.
Is there a plot available showing the INL? Have I made a mistake in my calculation? Are there different test methods being applied?
Your help is appreciated!