How to understand INL and DNL of an DAC/ADC

[Wamor]

inl and dnl

Hello,

For a testboard i need to use ADC and DAC. This board is used to test the analog functionality of a controller.
For the testboard i have selected the following DAC and ADC:
DAC: AD5611 from Analog Devices
ADC: ADC101S051 from National Semiconductor

The INL and DNL for the DAC are: +/- 4 LSB and +/- 0.5 LSB.
The INL and DNL for the ADC are: +/- 0.7 LSB and +/- 0.6 LSB.
I have selected these components on their low price and both have a resolution of 10-bits.

The controller to be tested uses the following DAC and ADC:
DAC: DAC8544I from Texas Instruments
ADC: ADS1240E from Texas Instruments.

The INL and DNL for the DAC are: +/- 0.098 %FSR (+/- 65 LSB) and +/- 1 LSB
The INL and DNL for the ADC are: +/- 0.0015% FSR (+/- 251 LSB) and +/- 1 LSB.
The DAC8544I is a 16-bits converter and the ADS1240E is a 24-bits converter.
Both chips have a significant higher price then then the ones i use.

I understand the the lower INL and DNL the better the converter but i do not understand why the lower priced converter have such better specs compared to the higher priced ones. Am i missing some point here and are DNL and INL the right parameters to compare the chips?

Best regards,

Wamor