I am checking our design using the AD5791 20 bit DAC in a circuit similar to that in application note CN0191. I want to check both the DNL and INL performance. I could measure the output at each input code but this will take for ever - well several hours. There is a very good application note from Analog by Walt Kester and Dan Sheingold - Chapter 5 Testing Data Converters that suggests something like 40 measurements can be made to determine the non-linearity. I have also just listened to Derrick Hawkins video 20-Bit Voltage Source Circuit for High Accuracy Applications where he mentions the non-linearities are measured at 1000 points. Presumably the 1000 point method supercedes the earlier technique.
Can you let me know what input values the 1000 point technique uses so I can replicate the method in my own measurement set-up?